Restoration and Maintenance An excerpt from the Dimension Stone Design Manual, Version VIII (May 2016)

Produced and Published by the Marble Institute of America 380 East Lorain St. Oberlin, Ohio 44074 Telephone: 440-250-9222 Fax: 440-774-9222 www.naturalstoneinstitute.org

© 2016 All rights reserved. No part of this document may be reproduced or transmitted in any form or by means electronic or mechanical, including photocopy, recording, or by an information storage and retrieval system, without written permission from the Natural Stone Institute. Restoration and study those sections thoroughly to gain a greater understanding of the subject matter. Maintenance – Stone geology 2.0 STONE FORMATION

1.0 INTRODUCTION 2.1 Thousands of stone deposits exist 1.1 One cannot effectively participate in throughout the world. Yet all stones have been the field of stone restoration without at least a formed by one of three methods, and therefore rudimentary understanding of the geological all stones can be classified into one of three sciences. Stone composition is a far more groups: Sedimentary, Metamorphic, and complex issue than is commonly thought, and Igneous. the in-service performance and behavior of the stone can be significantly influenced by even 2.2 The term Sedimentary comes from minor constituents of its composition. This the Latin word sedimentum, which means issue is further complicated by the fact that “sinking” or “settling.” It is used to describe while geologists and petrographers identify stone deposits that are formed when sediment hundreds of different rock types, the stone is collected over geological periods of time, industry uses much broader definitions of stone causing individual grains, or “clasts,” to be types than the scientific community. In doing cemented together by another agent. Common so, the industry includes similar materials into cementing agents, in descending order of various stone groups despite the fact that the preference, include silica, carbonate, iron stone does not technically and scientifically oxides, and clay. Limestone and sandstone are belong to that group. As practical examples, examples of sedimentary rocks. popular stones such as Crema Marfil and Rojo Alicante are commercially identified as 2.2.1 There also exist sedimentary stones “marble,” even though they are not geologically which are not created from the settling of marble, and would be scientifically classified as clasts, but are chemical sedimentary “hard, compact, dense limestone.” Paradiso stones. Onyx is an example of a chemical and Uba Tuba are commercially considered sedimentary stone. granite, yet they are actually “gneiss” and “charnockite,” respectively. The differences in 2.3 Metamorphic is a term used to composition, behavior, and performance describe stones that have undergone a change between these rocks and those rocks that in structure. The term originates from two scientifically belong in these classifications are Greek words: meta-, meaning change, and generally slight, and negligible in most morphic, meaning structure. Perhaps the best commercial issues. But to the restoration known example of a metamorphic rock is professional, such differences can be marble, which has changed its structure from a significant. Reference is made to the Marble sedimentary limestone to a recrystallized rock Institute of America’s Dimension Stone Design fabric known as marble due to intense heat and Manual Chapter 1 and Chapters 5 through 12. pressure. While a brief introduction of stone geology is offered here, a far more comprehensive 2.4 The term Igneous comes from the discussion of the subject can be found in those Latin word ignis, meaning fire. This term chapters. The reader is strongly encouraged to describes stones that were melted deep within

 2016 Marble Institute of America Stone Geology • Page 21-1 the earth by thermal energy released from the challenge to the restoration professional decay of radioactive minerals within the earth’s attempting to refinish it. The hardness of the core. These stones, eventually cooled and granite requires aggressive abrasives to solidified, have been harvested for a variety of effectively work the material, yet these same uses. Commercially, the most common of abrasives can create uncontrollable dishing and these rock types used is granite, yet many other gouging in the much softer travertine portions igneous rock types exist in commercial trade. of the floor. Variability in mineral hardness can also exist within one stone. Such variability can create the same challenges in achieving a 3.0 STONE MINERALOGY uniform level of grinding, and can also prevent a uniform level of gloss from being achieved

due to the difference in the light reflectivity of 3.1 Siliceous and Calcareous Stones. the two portions of the stone. Geologists have identified roughly 3,500 different minerals found in the earth’s 3.2.1 Mineral hardness has long been composition, yet only about a dozen of these measured by means of the Mohs Scale of minerals are commonly found in Relative Hardness. In 1822, Friedrich commercially-used stone varieties. As Mohs, an Austrian mineralogist, published a previously stated, however, even minerals paper on mineral hardness based on the scratch found in trace levels of a rock fabric can resistance of each of 10 minerals when tested influence the behavior and performance of the against the other 9 minerals in his study. His stone. Minerals that make up stone are published paper listed the 10 minerals in order commonly divided into two groups: siliceous, of their relative scratch resistance. As simple or silicate minerals, and calcareous, or calcium as this study appears, almost two centuries carbonate minerals. Stones that are comprised later, we are still using Mohs’ research and of siliceous minerals include granite, slate, and findings as the basic rank of mineral hardness. serpentine, while stones that are comprised of The ten stones included in Mohs’ scale include: calcium carbonate components include marble, limestone, and travertine. Hardness Mineral

1 Talc or Mica 3.2 Mineral hardness is an extremely 2 Gypsum important consideration for the restoration 3 Calcite professional. Mineral hardness determines 4 Fluorite how the stone will perform in service when 5 Apatite subjected to abrasion, such as stones used for 6 Orthoclase walking surfaces. Mineral hardness is also an 7 Quartz important measurement in predicting how 8 Topaz easily a stone can be resurfaced, as the grinding 9 Corundum operation can be significantly slowed when 10 Diamond hard minerals make up the stone fabric. In addition to the absolute hardness of a mineral, 3.2.2 There are two common one must take into account the variability of misconceptions regarding the Mohs scale. The mineral hardness within an installation. A first is that many do not clearly understand that patterned floor, using granite bands and the scale is relative, not absolute. travertine fields, can pose an extreme

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Relative simply means that “4” on the scale is a stone, but acidic chemicals are the cause of harder than “3,” and both of them are harder most frequent concern. Acidic chemicals are than “2.” The scale offers no absolute commonly found in both commercial and information regarding how much harder, or residential settings, through food and whether the interval between 4 and 3 is greater beverages, as well as many common cleaners or less than the interval between 3 and 2. A and detergents. One of the most frequent mineral with a hardness of 4 IS NOT twice as inadvertent acid exposures encountered in hard as a mineral with a hardness of 2. It is both residential and commercial settings is more than 10 times harder! Today, we have the urine, which is quite acidic and has been instrumentation available to measure absolute responsible for the attack of many stone floors. hardness. If the Mohs scale reported absolute hardness, it would look like the table below: 3.3.1 Acidic content is measured with the pH scale. The pH scale ranges from 0 to 14, Mineral Relative Absolute although there are some exceptionally acidic Diamond 10 1600 substances that can actually be below zero on the pH scale. A value of 7 is neutral; anything Corundum 9 400 lower than 7 is acidic, while anything above 7 Topaz 8 200 is alkaline. The pH scale is not a linear scale, Quartz 7 100 but a logarithmic scale. This means that a Orthoclase 6 72 substance with a pH of 5 is 10 times more Apatite 5 48 acidic than a substance with a pH of 6. Fluorite 4 21 Calcite 3 9 3.3.2 Generally speaking, all calcareous Gypsum 2 2 stones are subject to acid attack, even from the mild acids found in household Talc 1 1 settings. The most common result of acid 3.2.3 The second area of confusion exposure is etching, which is generally visible regarding the Mohs scale is that it is a as a dull spot in an otherwise high gloss hardness scale of minerals, not stones. polished surface. Depending on the acidity of Since nearly all stones are polymineralic, each the attacking agent, the dwell time that the mineral within the stone’s composition has its attacking agent was allowed on the stone own unique properties, including hardness. surface, the vulnerability of the specific stone Oftentimes we see marketing literature for a to acid reaction, and the number of repetitions certain stone that lists a “Mohs Hardness” for allowed to occur, the result can be much more the stone. This is a technical inaccuracy, since severe than a simple dull spot. the stone is comprised of a variety of minerals and each mineral has a unique hardness value. 3.3.3 Siliceous stones are far more acid To ask, “What is the Mohs’ hardness of this resistant than their calcareous stone?” is the equivalent of asking, “What is the counterparts. This does not mean that they flavor of Neapolitan ice cream?” It depends on are necessarily acid proof. Many siliceous which part of the stone, or which part of the ice stones include minerals of minor to trace levels cream, we are talking about. of concentration which are acid vulnerable. Additionally, certain acid types will attack 3.3 Chemical Resistance. There are a silicates. One of the better known examples is variety of chemicals that can attack the fabric of hydrofluoric acid (HF). This is a common component found in rust-removing stain  2016 Marble Institute of America Stone Geology • Page 21-3 removers and rust-removing laundry stain removers. Accidental exposure of stone to compounds containing low concentrations of HF is fairly common.

3.3.4 Degradation due to salt attack is included in this section, but despite the fact that salt is a chemical, its mode of attack on natural stone is not actually chemical, but mechanical. Salt is readily soluble in water, and when in solution, can penetrate the pores of medium to highly porous stone fabrics. When the water evaporates, the salt will recrystallize within the confines of the pore cavity in the stone. The expansion caused by the recrystallization exerts significant pressure on the walls of the pore, and is great enough to cause fracturing, resulting in an exfoliation of the stone face. Salt exposure is most commonly experienced in northern climates where salt is used as a snow melting chemical. The exposure is not limited to exterior surfaces, however, as the salt is carried into the building envelope by the footwear of pedestrians. Salt attack can be evident in both commercial and residential properties, but it is far more prevalent in commercial settings due to the greater use of salts in those venues. Limestone and travertine are the two most commonly affected stones due to their pore volume and pore structure.

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Restoration and 2.0 STONE FINISH IDENTIFICATION Maintenance – 2.1 The restoration professional must STONE identify the finish originally applied to a stone IDENTIFICATION surface. There are a variety of stone finishes in

the marketplace, many of them proprietary, but the majority of stone installations will have 1.0 FIELD IDENTIFICATION one of the standard finishes listed below. TOOLS 2.2 Polished surfaces are smooth, 1.1 Several simple field with a highly reflective, glossy face. The identification tools are available to level of gloss will vary from stone to stone, and measure hardness and acid sensitivity. can vary between different regions of a stone. Mohs Hardness picks can be purchased from Gloss level is related to both mineral hardness any number of laboratory or geology supply and pore space, so significant variation exists. vendors, generally for less than $100 per set. Gloss, or the level of reflectivity, can be This set of picks consists of metal and/or measured with a gloss meter, but no industry plastic tipped instruments which are calibrated consensus standard exists as to what level of to correspond to the values on the Mohs scale. gloss is required to define a surface as polished. One simply attempts to scratch the stone If such a standard were to exist, it would surface with the pick. If the stone is scratched, actually be different for each stone on the it is softer than that value; if it is not scratched, market. Stone polishing is strictly a it is harder than that value. The most common mechanical, abrasive process, with the field test for acid resistance is to use a diluted exception of some marble varieties, in which concentration of hydrochloric acid (HCl), oxalic acid might be used. It does not produce generally 5 or 10% concentration. The any level of pore closure, nor “mineral hardware store variety of HCl is muriatic acid, welding.” As such, polishing does not reduce which contains about 30% HCl. Many field absorption of the surface. However, it does technicians purchase the economical muriatic provide greater surface tension when fluids are acid and dilute it with water in a water to applied to it. muriatic acid ratio of 5:1 to 2:1. Placing a drop of the diluted acid solution on an inconspicuous 2.3 Honed surfaces are typically area of the stone surface will tell you if the produced with the same machinery used for stone is calcareous or siliceous. The acid will polished surfaces, with only a few of the final bubble and fizz when placed on calcareous abrasive heads removed. A honed surface has stones, such as marble, limestone, or the same flatness and perceived smoothness as travertine, while it will rest on the surface of a a polished surface, but has no or very limited siliceous stone, such as granite, quartzite, or reflectivity. Again, there is no industry slate, without any noticeable reactive activity. consensus standard that establishes the limits in Remember that this is an aggressive acid, even grit size or reflectivity that define the coarse after dilution. Safe handling practices with and fine boundaries of honed finishes. It is appropriate PPE are required at all times. commonly believed that honed surfaces have

greater frictional properties than polished surfaces. This is true in some extremely coarse grit honed surfaces, but in the majority of  2016 Marble Institute of America Stone Identification • Page 21-5 honed stones available in today’s marketplace, The most common stone to be supplied in a the difference in measured friction between cleft surface is slate, some varieties of which honed and polished surfaces is statistically cleft into extremely flat and uniform sheets. irrelevant.

2.4 A variety of textured surfaces 3.0 DETECTION OF SURFACE can be achieved in natural stones. TREATMENTS

2.4.1 Acid Washed, or “Acid Etched,” 3.1 Many stone surfaces today are treated surfaces are created by intentionally inducing with some type of surface-applied product, and an acid attack on calcareous varieties of stone, in many cases, multiple products. Recognition leaving a rough textured surface. The depth of and identification of these products is vital, as relief achieved is dependent upon the removal (or “stripping”) of them is frequently concentration of acid, vulnerability of the stone required to prevent an incompatibility with fabric to acid reaction, and dwell time of the subsequently applied products. The best acid application. scenario is if the owner has retained records of what has been used on the stone during its 2.4.2 Flamed, or “Thermal,” surfaces service life, from which the manufacturer can are created by briefly exposing the stone be contacted and exact chemistry and removal surface to a propane flame. The rapid heating protocol can be determined. Four groups of of the outermost crystals of stone causes surface applied products are discussed below. significant expansion and results in a thermal desegregation of the stone minerals. This finish 3.2 Sealers. True sealers are rarely used is typically limited to granite and granite-like in stone applications, as they prevent the stone igneous rock varieties, but some other stones from “breathing,” and often create vapor are also capable of taking a flamed finish. The pressures, blotchiness, or other negative depth of relief and related profilometry of the aspects within the stone fabric. There are a few surface is dependent upon the stone’s true sealers marketed for use on stone, but mineralogy, stone crystal size, and the setback, most commonly when a sealer is encountered, speed, and angle of incidence of the flame. it is a product that was not specifically formulated for stone, but intended to be used 2.4.3 Sanded surfaces have been textured on a different surface, such as wood. Sealer by abrasive particles striking the stone surface application can usually be detected by a at high velocities. Again, the finish “plastic-like” sacrificial surface compound on profilometry is dependent upon a multitude of top of the stone. factors, including the stone composition and hardness, particle size and velocity, and dwell 3.3 Impregnators are the most common time. product applied post-fabrication to stone surfaces. An impregnator can be solvent 2.4.4 Cleft surfaces are produced by carried or water carried. In either case, the splitting the stone fabric along its rift, or carrier evaporates after application, and the direction of preferred separation. Virtually all active ingredients, which may be a small stones can be cleft, but a much smaller variety percentage of the original formula, remain to of stones can be cleft to produce a surface that treat the stone surface. An impregnator is suitable and safe for pedestrian ambulation. “impregnates,” or penetrates, the surface and

Page 21-6 • Stone Identification  2016 Marble Institute of America remains below the surface to a depth of a reflective surface, unattainable in an untreated couple of millimeters, depending on the stone slab. The percentage of resin in the stone’s porosity and density. Impregnators finished slab differs for each stone slab. Most must be matched to the stone variety, as they overseas suppliers will not disclose the are designed for optimum performance on a application of a resin treatment on their slab specific range of stone properties. products. On rough slabs, the presence of resin Impregnators are usually detected by the treatment can usually be confirmed by stone’s reaction to water droplets; the greater observing the rough edges of the slab and surface tension of an impregnated surface will noting the cured drippings of resin. cause “beading” of water droplets. 3.5.2 Problems with resin treatment. 3.4 Dyes and some colored waxes are Although resin treatment does reduce the occasionally used by suppliers to alter the absorption of stone surfaces, it will not have natural color of a stone to a color that is more the same effect as impregnator treatment. desirable and in greater demand. The presence Resin treatment has long been associated with of a dye is rarely disclosed by the supplier. a darkening of the stone’s natural color, which Some dyes can be detected with a simple cloth can present challenges in matching the color saturated in a solvent. Acetone, methyl ethyl tone of an exposed polished edge to the treated ketone, and toluene are frequently used for this surface. Some resins may also complicate the purpose. Not all dyes are soluble with these application of impregnators due to solvents, so while this simple test might compatibility issues between the two products. confirm the presence of a dye, it cannot reliably No resin treatments have been proven to be confirm the absence of a dye. 100% UV resistant. Discoloration (yellowing) of the resin is possible, though not likely. Due 3.5 Resin impregnation prior to to the vast difference in rates of thermal polishing is common, especially in the expansion between cured plastics and natural countertop sector of the stone industry. The stone, dislodging of resin fillers is commonly most common resin used worldwide is epoxy, noted when such products are used in exterior but polyester and acrylic-based resins are also settings. Degradation of exterior surfaces is used. likely even without freeze/thaw cycling. As such, the use of resin-treated stone materials in 3.5.1 Process. Though resin impregnation exterior applications is not recommended. can be done entirely manually, most major stone slab sawyers and finishers use large, sophisticated process lines to perform this 4.0 IDENTIFYING REPAIRS operation. The sawn, unfinished slab is AND REINFORCEMENTS screeded with the resin product. It is then placed over a vacuum table, which draws the 4.1 Repairs and reinforcements are resin deeper into the stone slab, then placed in common and necessary in many stone varieties. an oven for accelerated heat curing. Once The restoration professional must be able to cured, the slab is sent to the polish line, where detect and identify such repairs, because some the majority of the resin is abraded from the modes of restorative procedures could slab. The residual resin exists only in the compromise the integrity of the fissures, cracks, pits, and other surface repair/reinforcement. A more comprehensive interruptions of the slab, offering a discussion of the allowable and anticipated cosmetically improved, uninterrupted  2016 Marble Institute of America Stone Identification • Page 21-7 levels of repair and reinforcement can be found not limited to these conditions, and can also be in the Marble Institute of America’s Soundness used on facing panels. The technique involves Classification document. cutting a groove, essentially a “dado,” into the back surface of the stone slab that is just slightly 4.2 Adhesive Repairs. Many repairs (not more than perhaps 0.020”) greater than and reinforcements are adhesive, in which two the diameter or width of the rod. The rod, portions of the stone have been re-cemented either metal or fiberglass, is fully encapsulated using a polymer adhesive. In some cases, this in epoxy (polyester is not effective in this is actually an intentional fabrication technique application) within the groove. If metal is (not a repair), such as using an adhered liner at used, many choose stainless steel over mild a countertop edge to create a visually thicker steel, due to the quality control aspects of edge. ensuring 100% unbreached encapsulation of the rod. This reinforcement technique is 4.2.1 Epoxy-based resins are best for unidirectional, meaning that it is only effective adhesive repairs that carry any amount of load, in reinforcing the stone when the slab is being because these products are stronger and have loaded in a manner that would cause the face to higher bond strengths and greater flexibility be concave and the back to be convex. than polyester-based resin adhesives. Rodding is also ineffective if the groove is excessively oversized, as the adhesive cannot 4.2.2 Polyester-based resin adhesives effectively transfer the strain to the rod and the are preferred by many fabricators and installers resistance back to the stone. The third because they typically offer lower cost, faster common error in rod installation is positioning cure time, and more easily-attained color the rod too deep, as the rod becomes less matches when dyed. Polyester adhesives are effective as its position advances toward the weaker and significantly more brittle than neutral axis of the stone. epoxies, making them a poor choice when high strength is required. However, this can be used 4.3.2 Sticking, or dowelling, involves as an advantage in some cases. If the seams of a two pieces of stone being fastened together kitchen countertop have been filled with using a stainless steel pin epoxy-adhered into epoxy, and the cabinetry moves, the stone is holes. This may be used to repair a cracked likely to crack, whereas as the same seam filled stone, or could be used as a higher strength with polyester would have yielded prior to method of adhesively bonding two stone units fracture of the stone. together. It may also be used as a secondary safety net in case the adhesive fails, such as a 4.3 Mechanical repairs. The use of dowelled liner block on the back surface of a adhesive alone is often inadequate to facing panel. accomplish the structural augmentation desired in the stone. A mechanical device may 4.3.3 Fiberglass mesh backers are used also be incorporated into the repair or to reinforce unstable slabs and tile to reduce reinforcement to achieve the required stability. the likelihood of fracture. This benefit is largely limited to the handling and transport of 4.3.1 Rodding is most commonly the slab. There is little permanent benefit after associated with kitchen countertop fabrication, installation. Fabricators frequently use this specifically in narrow regions such as the rail in technique in the interest of safety. If a slab is front of a kitchen sink or cooktop. Rodding is reinforced with a fiberglass mesh backer and is

Page 21-8 • Stone Identification  2016 Marble Institute of America fractured during transport, the fractured portion will be retained by the mesh, rather than falling to the shop floor and compromising safety. Like rodding, this reinforcement technique is unidirectional, meaning that it is only effective in reinforcing the stone when the slab is being loaded in a manner that would cause the face to be concave and the back to be convex. Two complications arise from the use of adhered fiberglass mesh backers. First, the back surface of the stone is truly sealed, eliminating vapor transfer at this point. Second, the ability of portland-based thinset to adhere to the epoxy coated back is severely compromised, and in most cases, effective bond can only be achieved by using epoxy- based thinset.

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NOTES:

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Restoration and the entire floor as the more labor-intensive material. In this case, the entire surface must Maintenance – be considered to be Emperador Dark. Emperador Dark (a geological limestone) is a Stone behavioral highly variegated brown commercial marble groups with multiple colored veins and textures ranging from white to tan to darker brown.

1.0 INTRODUCTION 1.3 There are exceptions to any rule in creating qualitative results on natural stone 1.1 In this section, stone varieties are surfaces. Most materials, however, will behave classified into behavioral groups to simplify the in predictable ways based on a sight evaluation process and create predictable classification. results across a broad spectrum of materials. Many stones can be applied to a particular behavioral group by sight. The technician 2.0 TYPICAL GROUP begins by visually identifying the behavioral CLASSIFICATIONS group based on common characteristics. It is important to have a general knowledge of stone 2.1 Marble, Travertine and and know the differences between marble, Limestone (referred to herein as MTL). travertine, limestone, granite, and other stone. There are two main behavioral groups for Physical characteristics and mineralogical calcareous stones: Consistent and Variegated. makeup are the primary influences of how a MTL is a broad generalization of almost all stone behaves. calcareous stone, and covers probably 80% of

Stone Behavioral Groups what will be encountered when evaluating restoration and refinishing jobs. Most MTL Consistent Variegated Quartzite/Granite floors can be treated with similar methods. Several specific trade names are used here as Crema Marfil Botticino Serpentine examples of stone products that fit into the described categories. These are examples only, Limestone Breccia Quartzite and do not represent a complete list of materials. The specific stones were chosen Travertine Emperador Granite because they are common and will be frequently encountered. The behavioral White Marble Green Marble characteristics are the most important information to retain. 1.2 To refinish Crema Marfil and Noce Travertine to any level of gloss will require the 2.1.1 Consistent MTL group. This group same actions from the technician. Each of these has a consistent overall color, with light to stones can be classified into the same behavioral moderate veining. While all stones are group. When considering how a stone will polymineralic, the stones in this classification behave during the restoration process, the will have one extremely dominant mineral in technician must look at the entire surface. their fabric. Veining in consistent material is Often there are two materials set into the same usually of one dominant color, as opposed to floor, either by design or mistake. Contrasting variegated stones, such as Emperador, and material such as Emperador Dark is frequently brecciated marble and limestone, which have used in accent pieces between Crema Marfil or multicolored veining trends. Crema Marfil is other class consistent tiles. If the accent pieces an example of the consistent MTL group. This require refinishing, the technician must treat stone is commonly commercialized as a  2016 Marble Institute of America Stone Behavioral Groups • Page 21-11 marble, yet geologically is a dense limestone. nicely, but lack the depth and clarity of other The surface is creamy white, with light to materials due to the difference in surface moderate veining. Most procedures and texture. These stones also wear out resin approaches for marble refinishing are based diamonds very quickly due to the fluctuation of from working with this stone. It can be soft/hard mineral content. They should be refinished with a typical set of resin diamond taken as high as possible with diamonds before marble abrasives and polished with most polishing and polished with a weighted marble polishing compounds. Stones that are machine and a traditional wet polishing comparable to Crema Marfil should be powder. repaired, maintained and refinished using similar methods. 2.1.3 Dense Limestone refers to any limestone that has a surface similar to marble. 2.1.1.1 Effective Techniques. Crema There are no visible holes or pits, and the Marfil is fairly soft when compared to other surface will usually have a consistent finish. marbles. Resin diamond marble abrasives This class of limestone is very hard compared should be used, usually starting with 220 grit to other limestone, and densities can easily be (depending on the severity of wear), and in excess of 160 lbs/ft³. Examples of this class ending with 1800 grit. This grit selection is would be Jerusalem (also referred to as based on normal wear and tear for this Ramon) and Jura Limestone. material. Lippage removal will require a more rigid and aggressive grit selection. A standard 2.1.3.1 Effective Techniques. Dense rotary buffer with a weighted drive plate is limestone is easier to repair, because the ideal for normal refinishing procedures. This adhesives will blend better compared to softer stone can be polished with a traditional wet- limestone. Dense limestone acts more like style polishing powder (usually containing marble than its porous counterparts, but will oxalic acid and tin oxide). It can also be still lack depth and clarity. This group will also polished with the newer wet-to-dry method. need to be sealed more thoroughly. This limestone is less abrasive than more porous 2.1.2 Porous Limestone refers to any limestone, but will still take its toll on limestone that appears to have a visibly porous abrasives. Dense limestone will sometimes not surface. Generally, these stones will have require the highest grit of diamonds when densities of less than 150 lbs/ft³. When looking refinishing, but in most cases should be taken closely at the stone, tiny pinholes are visible in through the full range of resin abrasives before the surface, without magnification. Two polishing. The full range of resin abrasives is common examples are Crema Europa from important because dense limestone is so Spain and the French limestone, Beaumaniere. delicate, its surface tends to become uneven These are both very soft, very porous, and and bumpy (called “orange peel”) when refinish using the same methods. polishing due to its delicacy. Because of this, a chemically cold powder (one that has a 2.1.2.1 Effective Techniques. The micro- relatively low acid content), or a two-step texture and inconsistent surface make this polishing procedure, should be used. By group difficult to repair. Most adhesives or following these recommendations, the highest patching material cure to a smooth, glossy clarity can be achieved without the risk of texture and stand out easily against the grainy, “orange peel.” matte surface of these stones. This group of limestone typically absorbs a lot of sealer in 2.1.4 Travertine. Despite the common order to properly protect: approximately 100 usage of the misnomer “travertine marble,” to 200% more than typical marble or travertine is a type of limestone. It is a travertine surfaces. These stones will refinish sedimentary stone that is formed naturally by

Page 21-12 • Stone Behavioral Groups  2016 Marble Institute of America existing limestone deposits that were marble, but they exhibit a larger, more defined dissolved, usually by hot and/or acidic springs, crystal structure. then transported to the surface where the material was allowed to settle and form a new 2.1.5.1 Effective Techniques. White stone deposit. Most travertine varieties behave Carrara and its relatives vary, even though they very similarly. They all naturally contain holes can look identical. They are somewhat softer or cavities. In many regions, travertine is the than other varieties of marble and should not most commonly used natural stone for floors. be refinished dry. This group will overheat and It is generally easy to refinish and repair. Its burn easily.2 Polishing should be done with a hardness is typically between that of limestone traditional style wet compound, although and marble. Travertine has a reputation for sometimes this group responds well to the wet- being hard to maintain in high traffic areas. to-dry process. These stones tend to be very Holes or pits can open or develop, which will difficult to repair due to their crystal-like then collect dirt, making the floor harder to transparency. Using solid color patching clean. Despite this, travertine is very material will stand out, even when matching serviceable and restoration efforts are nearly the correct color. A transparent epoxy or always successful. urethane should be used, taking precautions not to create a stain in the material. These 2.1.4.1 Effective Techniques. Travertine marbles stun very easily, resulting in noticeable can be refinished wet or dry, and can be solid white marks. Refinishing using a high grit polished with most marble polishing diamond abrasive is the best practice for this compounds on the market. Some travertine group. Carrara can “orange peel” easily and will varieties are vulnerable to stunning, yet typically have a very slight texture to it. susceptibility to stun marks is not a common characteristic of all travertine.1 Travertine is a 2.1.6 General Notes Regarding good material to use when learning how to Consistent MTLs. When polishing polish because it forgiving and difficult to over- consistent materials, ending with a lower grit polish. abrasive, such as 400 or 800 grit, a large amount of “hot” or acidic powder will be 2.1.5 White Marble. White Carrara needed to create a clear reflective finish. (Bianco Carrara) is what most people think of However, care must be taken to avoid the when they hear “Italian Marble.” It is a true “orange peel” effect. Consistent materials are geological marble. White Carrara is a white easier to clean, hone, and polish. marble with gray veining. The tone of the background and intensity of veining can vary. 2.1.7 Repairing Limestone and Because of the geological makeup, mostly Marble. Limestone and white marble will calcium carbonate, this material is consistent in absorb the solvent from some epoxy resins hardness throughout. Calacatta and Statuary when performing a repair. This can result in a (Bianco Statuario) marble are from the same stain around the perimeter of the repair. area of Italy, but are currently considered more Sometimes this stain can be removed, but most rare and exotic. Some Greek and Turkish of the time it is permanent. One way to avoid marbles are also similar to these types of Italian possible staining is to thoroughly seal the area to be repaired before applying any adhesive.

1 Stun marks are the result of explosions inside 2 Oxalic acid, which is used to speed the individual crystals in the stone. These marks polishing process, can burn marble. Burned are caused by sudden, pinpoint pressure marble has a dimpled appearance and a impacting the surface of the stone. molten, plastic shine. Rehoning is necessary to remove the burnt surface.  2016 Marble Institute of America Stone Behavioral Groups • Page 21-13

Another way to avoid this issue is to use a to use a finer resin diamond abrasive, up to patching material that will not create a stain. Be 3,500 grit, before polishing. The polishing step sure to test the patching material or consult the should also be more aggressive than normal— manufacturer prior to use. more pressure, friction and time is necessary. Good quality diamonds are highly 2.1.8 Cleaning Limestone. Thorough recommended. Because of the hardness of cleaning is required for most limestone these stones, granite diamonds can sometimes installations. While it may seem straight be effective. forward, there are some necessary precautions. Limestone is very porous, and oily cleaners 2.2.2 Other Types of Variegated may cause some discoloration, particularly marble include Rosso (with the exception of with extended dwell times. If this occurs, it can Rojo Alicante), Tennessee Pink, and the usually be removed with additional cleaning, various types of breccia. A short checklist can but prevention is a better practice than remedy be helpful in determining the steps necessary in this case. Limestone can take 24 hours or for refinishing variegated stone. Technicians more to dry out, so account for this when the should look for the following: color, veining, job involves sealing after cleaning. and color of veins in contrasts with color of field. 2.2 Variegated MTL Group. With MTL, if there is any question, it may be better 2.3 Consistent Variegated. There to treat the stone as variegated. Variegated exists a sub-classification of stones that could stones typically have a multicolored field and be termed “consistent variegated.” A prime multicolored veining. This look is caused by example of this classification would be the variety of minerals included in the stone Botticino. Botticino is very similar to Crema fabric, which in turn can lead to those differing Marfil (which is Class Consistent) and is also a minerals having a non-uniform response to the compact limestone but is a little different to abrasives and chemicals used in the restoration refinish. To the untrained eye Botticino can process. This class is considered more difficult sometimes be mistaken for Crema Marfil, but to polish and requires special proprietary it is harder. methods. To polish these surfaces, the restoration professional must use the highest 2.3.1 Effective Techniques. Botticino has diamond abrasives in the sequence and finish one characteristic that makes it drastically with chemically-cold polishing powders. different. It has white, cloudy minerals in it Another method is to finish with an ultra-high that do not polish easily. These areas tend to grit abrasive pad or powder. One example is burn or become very hazy as soon as they are Emperador Dark marble. Although most polished. They occur in different people refer to it as marble, it is a dolomitic concentrations across the different types of limestone, yet it is actually harder than most Botticino marble, but are almost always marbles. It is variegated, with veining that is present. Botticino should be handled the same affected differently than the other minerals in way as Crema Marfil, with the exception that the stone. the final polishing step must be done in a way to balance the polish and clarity so the white 2.2.1 Effective Techniques. Variegated areas do not burn. Sometimes, Botticino can be stones do not take a deep, glossy shine like refinished exclusively with fixed abrasives, up Crema Marfil or other similar materials, and to approximately 8500 grit resin diamond will typically have imperfections that can be abrasives without a polishing compound being seen with natural light. Refinishing requires a used. The quality of the abrasives plays a little more finesse than most marbles because critical role when using only fixed abrasives. of the variation in hardness. It is recommended Other times, polishing powders or liquid

Page 21-14 • Stone Behavioral Groups  2016 Marble Institute of America crystallizer can be used to finish the polishing understanding of the mineral composition of process. the surface will help the technician diagnose and correct issues. 2.4 Serpentine is a variegated stone with a marble-like appearance, but vastly different 2.5.1 Identifying Granite and mineralogical makeup. True serpentine is a Quartzite. Quartzite and granite are very silicate, is acid resistant, and will be similar. In general, these are the hardest significantly harder (Mohs = 5) than marble. decorative stones. Granite or granite-like stone Due to the absence, or near absence, of calcium can be easier to identify because of the granular carbonate, serpentine does not typically react crystal structure. A true quartzite can look with the acids in most marble polishing similar to marble, but is much harder. Since powders that aid the polishing process. For this quartz is the hardest mineral found in reason, technicians tend to treat serpentine abundance in granite, and since quartzite is surfaces more like granite. Many technicians nearly 100% quartz, it should be expected that prefer to use a crystallizer or low-acid, high- a true quartzite is even harder than granite. grit polishing powders and creams. Some This property can drastically increase the stones, such as Rosso Levanto, are variegated amount of time necessary flatten a floor to marble, but include large swaths of serpentine remove lippage. The best way to determine mineral in them. Rosso Levanto is a distinctive hardness is to perform a scratch test in an reddish-maroon marble with white veins and inconspicuous area. hints of green and other colors, and should be treated as a serpentine for purposes of 2.5.2 Effective Techniques. Granite and restoration and polishing. Most, but not all, quartzite are described as dense crystalline, but green marble-like stones are serpentine. the crystal structures of some varieties are very

porous. This is especially true on materials that 2.4.1 Effective Techniques. Serpentine are lighter in color, such as Giallo Ornamental, contains little to no calcium carbonate, and as Santa Cecilia and Kashmir. It is very important such, will not react to traditional marble to use a high quality impregnating repellent to polishing powders. It can be etched and minimize the darkening of the stone caused by scratched, but not at easily as other MTL absorption of water or other liquids. When surfaces. When refinishing, it should be treated polishing dense crystalline surfaces, the like granite. Using diamond abrasives and technician will often follow the same steps. polishing compounds made for granite will be These stones must be refinished using effective when working with serpentine. This mechanical methods with abrasives to achieve group will not display a deep gloss or present a the highest possible shine, because they do not lot of clarity like marble. react with conventional polishing powders and

creams. This process takes a lot more time than 2.5 Granite and Quartzite. Most dense polishing softer materials. The technician must crystalline materials behave similarly and can take this into account when scheduling and be classified into the same section. It is bidding the project. Scratch removal on a important to note that many of the “granite” granite countertop can take up to five times materials evaluated may not actually be longer than the same scratch on MTL. Even granite. Many of the “granites” with veining are though this group can be drastically different actually gneiss. Solid black “granites” are from one another, they are all refinished with usually gabbro. The main concern here is to the same processes and techniques. A granite- simplify the selection process and avoid specific diamond abrasive is used for both. The confusing the end-user. In other words, if it major difference between the two is the final performs like granite in use, then it should be polishing step; quartzite requires several more called granite. While this may not always be applications of the final polish, and usually with important to complete the project, a broader  2016 Marble Institute of America Stone Behavioral Groups • Page 21-15 much more pressure. There are several ways to approach the final polish that will allow the stone to be polished back to a factory finish or better. Because these stones are so hard and typically found on countertops, which are closer to eye level, there is little to no room for error when refinishing. Even the slightest pf waves, ripples, or gloss inconsistencies are visually noticeable. Selection of the right type of abrasives and good quality tools is paramount to a successful restoration of these materials.

2.6 Sandstone is an extremely porous silica-based stone. The term “sandstone” describes the clast size (1/16 to 2 mm), rather than mineralogical composition. Sandstone can therefore be of a variety of mineral types, although the most common found in dimension stone use is quartz-based sandstone. The material that cements the clasts together has more influence on its performance and behavior than the actual sedimentary clasts.

2.6.1 Effective Techniques. The surface of sandstone looks and responds like fine sandpaper. It will wear out abrasives very quickly. Sandstone is not frequently refinished as often as it is simply cleaned. If there are scratches that need to be addressed, honing can be done similar to a hard limestone. The material will not take a glossy finish. Sealing can be time consuming and costly, because the high absorption and porosity of the stone requires multiple applications of generous amounts.

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Restoration and into the material’s behavior in various environments, as well as its porosity, density, Maintenance – hardness, and other inherent characteristics. Diagnostics For example, more porous limestone may require more regular maintenance, such as additional sealer applications when installed in 1.0 INTRODUCTION a wet environment. Similarly, a polished marble floor in a commercial application can be 1.1 The word diagnosis comes from the better protected against scratching and traffic Greek word diagignōskein, which means “to pattern wear by the use of walk off mats. distinguish.” It aptly describes the process that the restoration professional must accomplish 2.2 Location. A stone’s behavior can during the earliest phases of the project, even differ depending on the environment in which prior to submitting a proposal to the client for it is installed. For example, the performance of performing the necessary work. Without a the same stone may be markedly different in proper diagnosis, it is not possible to prepare high traffic versus low traffic areas, or in wet an accurate estimate of costs, time, or areas versus reasonable expectations for the quality and performance capability of the stone after 3.0 EXISTING INSTALLATION completed restoration. A thorough and accurate diagnosis requires distinguishing METHOD between symptoms and the problems creating 3.1 The methods with which the stone was those symptoms. For example, cracks or dull originally installed must be verified before spots in a stone floor are merely symptoms, restorative work may commence. Stone will and while those symptoms can be cosmetically naturally age and wear throughout service. treated, they will reappear if the root problems Knowing the age of the installation helps that caused them are not addressed. A determine if the condition of the stone thorough onsite inspection is necessary to represents normal aging and patina, or an provide the most accurate proposal and abnormal, premature degradation of the treatment recommendation. In some product as a result of conditions that need to be situations, identification and remedy of the corrected. problems may exceed the level of expertise of the restoration professional, requiring the 3.2 The method of attachment used in consultation of additional professionals. The an application must be determined to ensure items addressed below provide a general guide that the planned restorative techniques will not for the diagnostician to accomplish this task. compromise the attachment. It also must be verified that the method of attachment is still stable and reliable. If this is not verified, an 2.0 STONE TYPE installation could be cosmetically restored, but then fail structurally. The simplest methods of 2.1 Identifying Stone Types. attachment involve adhesive bonding only. Identification of the stone by customary trade Floor and wall tiles are typically held in place name may not always be possible, nor is the by adhesive methods only. When the stone country of origin always identifiable. The becomes thicker, starting at 20 mm and geological type of stone must always be greater, mechanical anchors may have been confirmed. This information provides insight

 2016 Marble Institute of America Diagnostics • Page 21-17 used in combination with or in lieu of the lbs/in², and the 20 mm stone is a high strength adhesive bonding. stone with a flexural strength of 2,500 lbs/in², the 20 mm section is actually stronger in 3.3 Resources for Tile and service, despite its reduced thickness. When Mechanical Anchors. Most adhesively- grinding operations are required, one must be attached floor and wall applications have been careful to not only avoid grinding through the installed using methods outlined in the Tile stone depth, but also grinding the stone to such Council of North America’s (TCNA) Handbook a reduced thickness where it can no longer for Ceramic, Glass, and Stone Tile Installation. perform under load. It must also be Readers are encouraged to obtain a copy of this ascertained that the stone is solid through its publication (available for purchase through depth, as opposed to stone-faced units MIA’s Online Bookstore) and familiarize consisting of a very thin layer of stone themselves with it prior to evaluating existing laminated to ceramic, metal, or other backer tile installations. Readers are referred to MIA’s units. While joint fillers can be abraded to Technical Bulletin, “Dimension Stone facilitate viewing and measurement of the Anchorage; Theory, Practice, & actual stone depth, a far easier and less invasive Components,” for a comprehensive discussion method is to take advantage of the existing of mechanical anchorage techniques. A mechanical and electrical penetrations. Simply mechanical anchor is any device (usually a non- removing a grate over a heating duct or corroding metal such as stainless steel, removing the plate over an electrical switch or aluminum, copper, brass, or bronze) used to outlet will usually confirm the actual thickness secure the stone unit to an unyielding support, of the stone units. Stone thickness can often be such as the building frame. Anchors are nearly ascertained at the doorway to unfinished space; always concealed in stonework, so the for instance, where the stone work truncates at restoration professional must verify their the transition between a finished space and an location and ensure that the restorative unfinished utility room. procedures will neither expose them nor compromise their integrity. 5.0 EVALUATION OF DESIGN AND EXECUTION 4.0 MEASURING STONE THICKNESS 5.1 The existing design and installation must be evaluated for a series of potential 4.1 The thickness of the installed stone deficiencies. If deficiencies are noted, the influences which restorative techniques may be condition must be corrected as part of the attempted, and how aggressively those restoration process, lest post-restoration attempts may be implemented. Stone failure is likely. thickness should be evaluated in conjunction with stone strength. In flexure (bending), a 5.2 Five Categories of Movement stone’s strength is proportional to the square of Joints. A series of specialty joint designs is its thickness. Therefore, a 30 mm thick section necessary in all finished stonework to facilitate of stone is over twice as strong as a 20 mm thick dynamic building frame movements, section of the same stone (30² = 2.25 x 20²)! differential thermal expansions and But if the 30 mm stone is a relatively low contractions, and permanent deformation strength stone with a flexural strength of 1,000

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(creep) of structural units. These necessary develop their resistance to applied loads. functional joints are frequently omitted from There are two primary components to consider stone installation designs, and their absence is when evaluating whether or not the substrate one of the most common contributors to stone has the required rigidity to adequately support installation failure. These joints can be placed the stone units. into five general categories: 1: Expansion joints typically go through the stone 5.3.1 Frame Deformation must be held installation assembly and building structure, to extremely low allowable deflections. and accommodate relatively large movements Various documents (building code, ACI, and anticipated in the building frame at that MIA) list a maximum allowable deflection location. 2: Isolation joints are also anywhere from L/600 to L/1000. In addition typically carried through the building to the basic deflection of the framing members, structure, and are most often used to bridge one must verify that the potential differential between different structural elements; for deflection between adjacent members is not instance the separation between a footing pad excessive. Oftentimes, some type of load- at a column and the surrounding concrete slab. sharing device is required to tie adjacent 3: Control joints are merely shallow cuts in members together and reduce the inter- concrete slabs which create a slightly weaker member differences in deflection under load. zone and direct, or “control,” where shrinkage Since deflection and radius of curvature are not cracks will occur as the concrete cures. 4: exactly the same thing, span length also Perimeter joints separate the finished stone becomes part of these analyses. surface at regions of discontinuity, for instance where horizontal finish planes intersect with 5.3.2 Substrate Panel Deformation. vertical elements, such as walls or columns. 5: The substrate panel, be it a sheathing on a wall Generic Movement joints are simple soft assembly or a subfloor/underlayment joints occurring in the finish stone surface only, combination in a floor assembly must be and are intended to provide an interruption in sufficiently stiff to carry the loads experienced the accumulation of shear stresses resulting by the stone units back to the framing members from differences in temperature or expansion without undue deformation. rates between the stone and the rest of the assembly, or to accommodate differences in 5.4 The setting adhesive used, if elongation or compression as a result of floor possible, should be identified to verify its curvature. Refer to section EJ171 of the suitability and the quality control of its TCNA’s Handbook for Ceramic, Glass, and Stone placement. Tile Installation for additional information on these types of joints and requirements for their 5.4.1 Appropriate Selection. Certain frequency in stone designs. stone types require specific types of adhesives; for instance white colored thinsets are required 5.3 Substrate Rigidity. Stone is a quasi- for light colored marble and limestone, and brittle material and does not bend easily. A 12” epoxy-based thinsets are required for mesh- x 12” x 3/8” stone tile could fracture with as backed stones and many moisture sensitive little as 0.010” total deformation! As thin stones. stone tiles (less than 20 mm thickness) are considered to be decorative, abrasion- 5.4.2 Adequate Coverage. The adhesive resistance finishes only, they must rely on the must have adequate contact area with the stone rigidity of the substrate and bedding layers to unit. MIA’s Dimension Stone Design Manual calls  2016 Marble Institute of America Diagnostics • Page 21-19 for 95% contact with no voids exceeding 2 in² checking for lippage issues is to use a standard and no voids within 2” of tile corners on 10 mm plastic credit card as a gauge, since most credit tile. In 20 mm thick stone, 80% contact with cards measure ±0.030” in thickness. no voids exceeding 4 in² and no voids within 2” 5.6 Wet Areas. Water infiltration of a of tile corners is required. All corners and stone system is always a concern, particularly if edges of stone tiles must be fully supported and the stone system was not designed for water contact shall always be 95% in water- exposure. Evaluation of a proposed restoration susceptible conditions. project should include careful study of water control and flow, as well as evidence of water 5.4.3 Bond Strength. Adequate bond damage. In many cases, water damage repair strength may not be achieved between some requires complete removal and replacement of thinsets and stone materials with compromised the installation, since the damage may be bonding surfaces, such as those that have had concealed by several layers of the installation mesh backing applied, or those that have been system and is not accessible without sealed or resin-treated on their bonding excavation. surface. 5.6.1 Water Control Slopes. Water flow 5.5 Stone Jointery Alignment is governed by gravity, therefore, sloping of influences both performance of the system and surfaces toward a drain or other path of aesthetics of the finished installation. effective evacuation is a necessity that cannot be compromised. In general, any slope of less 5.5.1 Joint Width Tolerances. The than 2% (¼” per foot, or 20 mm per m) is installing contractor is allowed a tolerance of ineffective in achieving positive water flow. the greater of either 1/16” (1.5 mm) or 25% Inadequate slope is a condition that cannot be of the specified joint width when installing corrected in normal restorative procedures. stone units. Many existing installations do not One must carefully guard against reducing or comply with this tolerance. The issue can often eliminating existing water control slopes be remedied by field cutting joints during the during restorative processes. restoration process. A wider joint of a uniform dimension will look better than a narrower 5.6.2 Drain Function. If the goal of the joint of varied dimensions. sloped surfaces is to direct water to a drain, then achieving that goal is useless unless the 5.5.2 Lippage Tolerances. Stone flooring drain is fully functional to evacuate the water units are typically supplied with little or no once it arrives. Drains must be inspected for chamfer at their perimeter, and are typically proper operation, and in particular, subsurface installed with narrower joints than other hard weep holes in the drain assembly must be surface flooring products. These factors checked for proper water flow functionality. accentuate the perceived lippage, both from a visual aspect as well as an occupant safety 5.6.3 Efflorescence is a collection of aspect. Lippage tolerance between adjacent water-soluble compounds (typically salts) that units of smooth finished stone flooring units is have been carried to the stone surface by water. limited to 1/32” (<1 mm). The easiest way to Efflorescence deposits typically carry two or measure this is with a digital caliper, using more of the following: potassium, sodium, 0.031” as the maximum allowable calcium, sulfates, carbonates, bicarbonates, measurement. A common method of field and hydroxides. In some cases, the water

Page 21-20 • Diagnostics  2016 Marble Institute of America soluble compound can chemically combine further complicate the task of restoring the with other compounds at the surface, creating stone. In extreme cases, the stone may have a non-water-soluble compound. The key to been altered beyond a state from which it can preventing efflorescence is to control water effectively be restored. Candid migration. This may or may not be remediable communication with the client is imperative to in some restoration settings. Refer to ASTM establish reasonable and attainable expectations C1400, Standard Guide for Reduction of for the project’s outcome. Efflorescence Potential in New Masonry Walls for further guidance in this subject. 6.3 Staining does occur in natural stone. However, the stain potential of natural stone has perhaps been overhyped by 6.0 EVALUATION OF marketing claims made by producers of OCCUPANT AND IN-SERVICE competing materials. INDUCED CONDITIONS 6.3.1 The most important step in stain removal is to identify the staining agent. 6.1 Current Maintenance Products If this is not achievable by interviewing the and Procedures. A review of the products building occupants and maintenance staff, one used and the procedures followed will provide must speculate as to what the staining agent insight into which professional maintenance likely could have been based on available treatments are to be prescribed for a situation. information. Information used in this Some cleaners used by end-users can be speculation includes the stain color, shape, harmful to the stone. These products may size, location, frequency, and a list of potential cause blemishes that require removing (i.e.: staining agents commonly found near the site acidic cleaners that cause etching, abrasive of the stain. cleaners that create dullness, oil-based surfactants that cause residue, or wax-based 6.3.1.1 Food and Beverage Stains include cleaners that cause build up). Knowing which natural pigments (i.e.: fruit, juice, or wine cleaners have been or are being used will help stains), dissolved solids (i.e.: coffee stains), and determine the best cleaning techniques oil-based stains (i.e.: cooking oils or meat fat available. One challenge in determining these stains). Food and beverage products may also things is that the owner may not be the original be acidic and contribute to etching of owner of the property, and therefore calcareous stones. unfamiliar with the entire history of maintenance procedures. A second challenge 6.3.1.2 Rust Stains are generated by contact exists in that most owners do not perform their or close proximity to corroding metals. Rust own maintenance, and are unlikely to be stains are some of the most difficult stains to familiar with which products and/or eradicate. The source of the rust may be procedures were used by employees or concealed by the stone assembly, such as a vendors. corroded fastener in substrate layers. In rare cases, the origin of the rust is a metallic-rich 6.2 Previous Restoration Processes. mineral within the stone fabric. Rust stains A restoration professional is often contacted that originate from within or below the stone due to dissatisfaction with work performed by are generally not removable, since the source another company. Correction of previous, of the stain cannot be eliminated. inappropriate restoration processes will  2016 Marble Institute of America Diagnostics • Page 21-21

6.3.1.3 Soiling occurs when dirt mixed with material. The crack may be the result of a oil or grease scratches, dulls, or discolors single occurrence trauma, in which case the porous stone and grout. More porous stones, crack may be repaired without addressing the especially those pores visible to the naked eye cause, as long as there is reasonable confidence (i.e.: limestone & travertine) are most that the trauma will not be repeated. When vulnerable to soiling. Aggressive grinding or multiple cracking occurs within a stone chemical treatments may be required to installation, it is generally the result of a restore the stone’s color. In extreme cases, repeated occurrence (i.e.: excessive loading soiling may be cost prohibitive to remove. that occurs on a frequent basis), or a design/workmanship deficiency (i.e.: 6.3.1.4 Efflorescence (as discussed in inadequate substrate rigidity or insufficient section 5.6.3 above) is always the result of bedding coverage). In these cases, the cause of water-soluble compounds carried to the the cracking must be identified and corrected surface by water migration. In most cases, the prior to the repair of the cracks to avoid stain is easily removed, but reoccurrence is a repetition of the cracking. certainty unless the water migration can be arrested. 6.4.1 Impact Cracks and/or Chips are caused when a heavy object falls onto the 6.3.1.5 Hazing is most frequently the result surface or when a heavy object is moved across of improper or incomplete cleaning after the the floor. In soft stones, the crack may be initial installation. The source of the haze is accompanied by a depression in the stone frequently grout, although it can also be a surface. A white or light crack “stun mark” is result of inappropriate or incorrectly applied often visible in addition to the crack. These sealers. Some grouts are so prone to hazing types of cracks are typically due to a one-time that masking the stone during grouting is the experience. only way to reliably prevent hazing. 6.4.2 Cracks caused by excessive 6.3.1.6 Grout Stains. All agents that can loading. Excessive loads may occur from cause stains in stone will also cause stains in vehicles, freight delivery dollies, furniture, or grout. Due to the high porosity of grouts, the other sources. These may be individual or same type of stain may penetrate deeper into repeat occurrences. If the latter, customer grout than it will in stone. education is paramount to ensure that the practice of excessive loading is discontinued 6.3.2 Eradication. Nearly all stains can be after cracks are repaired. removed from nearly all stone types. Stain identification is key; after identification, the 6.4.3 Cracks caused by building removal can generally be accomplished quickly movement. Dynamic building movements and effectively using proven methods. If the can be caused by foundation settling, thermal origin of the stain is unidentifiable, varying expansions/contractions, frame deflections, levels of trial and error are usually required. creep, and seismic or wind loads. With the exception of foundation settling, all of these 6.4 Cracks. A crack is a separation of the movements should be anticipated, and the stone fabric, typically along a grain boundary. failure of the stone installation suggests an Cracks are easily visible. In most situations, improper design. they extend through the entire thickness of the

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6.4.4 Cracks due to improper stone heeled shoes are common causes of exposing installation. Voids in the setting beds, these voids. inadequate accommodation for thermal expansion, or failure to use appropriate 6.8 Scratches are commonly caused by membranes where required are frequent grit beneath shoes or furniture, sliding objects, factors in cracked stone flooring and paving. or maintenance equipment with improper, worn, or dirty cleaning heads. The severity of 6.5 Chips and Spalls are most often a scratch can be assessed by running one’s caused by impact from dropped objects or fingernail across it. If the fingernail pauses or rolling loads with hard wheeled equipment. catches in the scratch, it will normally take The client needs to understand the cause of the more aggressive measures to eliminate it, but problem to prevent further damage after scratches that do not catch a fingernail are restoration. usually minor and can be eliminated with refinishing. 6.6 Etching is a dull whitish mark that results from a chemical reaction between a 6.8.1 Scratch removal can be caustic or acidic liquid and calcium carbonate accomplished through abrasive grinding, in stones like limestone, marble, travertine or refinishing, and honing. The depth of the engineered marble (man-made marble). The scratch determines the coarseness of the initial depth of etching may vary, from a minor grit needed to remove it. Trial and error surface attack representing itself as a dull spot iterations may be required before one knows on an otherwise glossy surface, to a deep attack what starting grit is required. More with a penetration of a millimeter or more experienced technicians may intuitively know where a textural difference can be felt with which grit is needed to start the process. one’s fingers. Simply cleaning, polishing or resealing will not remove an etch mark. To 6.8.2 Pressure Scratches actually damage completely remove the mark, it must be the body of the stone tile through compression ground to the depth of the damage and and gouging. These types of scratches are refinished. usually permanent, but can be minimized.

6.7 Pits and Voids (holes, fissures, 6.9 Topical Sealers (also referred to chips, cavities, veins, etc.) are common for as film-forming sealers and coatings) various stone types. Materials are filled with differ from impregnating (also known as either resins or cementitious fillers during penetrating) and enhancing sealers in that they factory processing, or less frequently, in the create a sacrificial coating on the stone’s field during installation. Over time, the filling surface as they cure. These products must be can dislodge, requiring replacement during stripped before maintenance or restoration maintenance or restoration. Some stones, attempts. Topical sealers contain waxes, notably fleuri cut travertine, will have voids acrylics, urethanes, and other chemicals that just below the surface of the stone concealed by are high in solids – therefore, they do not a thin shell of stone fabric. These voids do not penetrate the pores as effectively as get filled due to their concealment, and are impregnating repellents. Since they do not likely to be exposed as the shell of stone allow for vapor transmission, moisture can be covering them is broken during service. trapped within the stone. Additional Rolling loads with small diameter, hard undesirable traits of topical sealers include wheels, and concentrated loads such as spike color change (yellowing), flaking, dirt  2016 Marble Institute of America Diagnostics • Page 21-23 attraction, vulnerability to scuffing, frequent a level where restoration is achievable. reapplication intervals, and labor intensive Horizontal applications are more severely removal processes. affected than vertical, and grout distress usually prefaces or accompanies stone degradation. 6.10 Close grout examination is one of the more critical components of the site 7.3 Water Damage. With or without inspection. Grout is softer, more porous, and freeze/thaw cycling, water ponding and water less resilient than stone. Grout will frequently transmission through the stone can break down show signs of distress before similar signs of either the stone fabric, the bedding layers, or distress are noted in the stone components of both. Excessive water exposure and ponding the installation. Sanded grout is most can result from inadequate drainage, commonly used when stone tiles have been improperly prepared substrates, insufficient or installed with relatively wide joints (≥3/16”). negative slope, ineffective moisture Since the sand in these grouts is harder than membranes, or ground water transmission. some stone varieties, scratching may have These can result in various issues, such as resulted during the grouting process if the excessive mineral build up, mildew and moss stone was not adequately masked. Additional accumulation, damage from the expansion and scratching may occur during the restoration contraction of more porous materials, surface processes if the sanded grout is not removed exfoliation, and distress in the setting beds prior to restoration. and/or grout.

7.4 Saltwater Environments (regions 7.0 ADDITIONAL CONSIDER- near oceans). Stone applications near ATIONS FOR EXTERIOR APPLI- saltwater environments may experience CATIONS additional degradation due to exposure to salts. Salts attack the more porous varieties of stone

via a mechanical, rather than chemical mode. 7.1 Weathering. Weather exposure When salt is carried in solution by water, it causes a degradation of the stone surface over penetrates the pores of the stone. As the water time. The degree of weathering is dependent evaporates, the salts recrystallize within the on both the type of stone and the severity of the confines of the pores, and this recrystallization environment in which it was installed. pressure is great enough to exfoliate the stone Weathering includes both physical and surface. Some sealers have proven to be chemical attacks. It should be noted that some effective in minimizing the effects of saltwater stones are simply not exterior-worthy environments, or at least in retarding the rate materials, and no level of restoration can of attack. effectively compensate for an improper selection of a stone material. 7.5 Pool/ hot-tub/ resort/

commercial center environments. 7.2 Freeze/thaw issues. In regions Exterior applications of natural stone in high where freeze/thaw cycling occurs, weathering traffic and wet environments should be can extend beyond cosmetic issues and become inspected for various post installation structural issues. It is not uncommon for treatments that may have been applied to help improperly chosen stone species in improve slip resistance. Some stones may have freeze/thaw environments to degrade beyond been exposed to treatments such as acid

Page 21-24 • Diagnostics  2016 Marble Institute of America washing, brushing with abrasive-embedded 8.2 BUILDING CONTENTS brushes, or coated with topical finishes 8.2.1 Furniture and other items. containing grit. Moving furniture exposes the restoration

contractor to additional liability in having 8.0 PREVENTING DAMAGE TO his/her crews handle items for which they have ADJACENT SURFACES AND not been trained. Moving a piano, for instance, BUILDING CONTENTS is best handled by those who are professionals in that line of work, and in either case, is likely 8.1 SURFACES to result in the owner having to retune the instrument after it is returned to its original 8.1.1 Adjacent Floors. The maintenance position. or restoration processes used on natural stone may damage adjacent flooring materials. It is 8.2.2 Artwork and Antiques. Specialty best to anticipate possible damage and take items, such as artwork and antiques, can be steps to protect these surfaces in the beginning. valued at more than what the restoration

professional’s contract is. It is strongly 8.1.2 Adjacent Rooms and Access encouraged that these items be handled by Routes. Adjacent rooms are best protected by someone who is trained in this activity and sealing the halls/doors that lead to them, specifically insured for the liability incurred. particularly is any dry working will be performed. Access routes along which materials or equipment will be transported 9.0 UTILITIES AND ACCESS must be fully protected from damage to any of 9.1 Power Source. Prior to preparing an their surfaces. estimate for performing the work, it must be verified that adequate electrical power is 8.1.3 Baseboards and Walls. If light available (both required voltage and honing and polishing is the only process amperage). If this is not the case, the cost of needed, then it is only necessary to protect the providing generators must be considered. base during the work. More aggressive restoration techniques, such as lippage 9.2 Water Supply. If adequate quality removal, require the base to be removed. and quantity of water are not available onsite, Depending on the material used for the base, considerable cost will be encountered in removal and reinstallation may require a bringing water in from an outside source. different trade be involved to assure quality workmanship results. 9.3 Water Discharge and Disposal. It must be verified if water discharge and disposal 8.1.4 Thresholds and Transition can be accomplished at the site, or if spent Strips. If the threshold is stone, refinishing it water supply and/or slurry needs to be should be part of the stone restoration process. removed from the site. If it is of a different material, it may be necessary to replace it after completing the 9.4 Building Occupants. Working in project. an occupied building may limit the hours available to the restoration contractor, and may also limit to number or size of areas that can be worked on at a time to avoid inconveniencing

 2016 Marble Institute of America Diagnostics • Page 21-25 building occupants. Early communication with these cases, a consultant experienced in stone the client is essential in determining a sequence tile forensics should be contacted. of work areas and establishing an estimated duration for the project. 10.4 Inadequate structural support and/or building movement issues. If 9.5 Business Schedules. Few business either of these is suspected, a consultant who is can absorb the cost of suspending their business licensed to practice in that jurisdiction should during restoration. This may mean that the site be involved in the analyses. is available only after hours or weekends. It also may add costs in daily cleanups and removal of 10.5 Substrates with high moisture. equipment to allow the business to continue Some issues involving substrates with higher with only minor interruptions. moisture levels can be mitigated through the use of a moisture retardant membrane. These 9.6 Noise and Dust Restrictions. barriers have varying levels of effectiveness. Clients and neighboring homes or businesses The following are some of the issues caused. may have legitimate objections to the creation of noise or dust. Any possible restrictions must 10.5.1 Stained Stone. Subsurface water, be researched in advance. with or without impurities, will result in surface discoloration or staining of the stone. 10.0 SERIOUS ISSUES THAT Removal of this discoloration is an ineffective REQUIRE RESEARCH AND MORE solution unless the source of the moisture can EXPERIENCE be eliminated.

10.1 The restoration contractor must be 10.5.2 Stained Grout. Just as the stone can aware of the limits of his/her experience and be stained, the grout will be stained as well, expertise. Following is a partial list of possible often to a greater degree. scenarios which may require the consultation of another professional. 10.5.3 Efflorescence requires the presence of water soluble salts in subsurface levels that 10.2 Structural Problems. Any are carried to the surface by moisture symptom that suggests a structural problem transmission, where they then recrystallize with the building may exist: Extensive after the moisture evaporates. Elimination of cracking, chipping, grout distress, or the moisture source or addition of a barrier to misalignment may indicate a structural issue the moisture path are the only permanent with the building foundation or frame. If solutions. structural issues are suspected, a consultant who is licensed to practice in that jurisdiction 10.5.4 Moisture Hazing. Generally, a non- should be involved in the analyses. stone substance, such as a sealer or resin, is the affected component when hazing at the surface 10.3 Extensive hollow sounds or has been triggered by chronic moisture adhesion problems. While epoxy injection transmission. or grout replacement may be a feasible remedy for limited occurrences, extensive hollow 10.5.5 Spalling and other factors. This sounds or adhesion failures may represent a may indicate water migration or higher systemic problem with the stone installation. In moisture levels.

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Restoration and speed up the process. Weights vary in size and shape depending on the manufacturer, but they Maintenance – typically mount on top of or around the motor housing. The weight of the machine while EQUIPMENT grinding should be approximately 200 pounds (90 kg). 1.0 INTRODUCTION 2.1.2 Diamond Honing and Polishing. 1.1 A complete list of equipment used in When diamond honing and polishing (220 resin the process of restoring or maintaining stone grit through a powder polish), generally the would be very extensive. Individual faster the speed of the machine, the more preferences can dictate the need for a wide weight you will need. Most floors requiring variety of items. The primary focus of this refinishing are 12 to 18-inch (300 to 450 mm) section is to identify and describe the most square tiles. The diamond abrasives need a common equipment used in restoring, minimum time on each tile to cut. If the refinishing and maintaining stone. machine is moving too quickly, the abrasives will not make a thorough cut. Adding weight to the top of a faster machine (200 RPM or 2.0 FLOOR MACHINES faster) will add pressure to help the abrasives dig in a little more and speed up the process. 2.1 Mono-rotary machines are an On European-style machines, the motors are absolute “must have” for stone usually much slower (150 RPM). This restoration companies. Because mono- eliminates the need for the extra weight, rotary machines utilize a single, often rigid, because the diamonds spend more time on each drive plate; with the correct abrasive they can tile. Either configuration can yield the same be good for edge work on floors. Mono-rotary results. machines are single disc, single speed machines. The most common type is a 17-inch 2.1.3 Mono-rotary machines have (430 mm), 180-RPM machine. They weight many attachments (most commonly, approximately 85 to 95 lbs (39 to 43 kg). brushes). A light duty nylon brush can be Speed and weight vary with the manufacturer, used for scrubbing and rinsing polished stone but “180 RPM mono‐rotary” is the general floors without scratching them. Brush description used for what has become the most attachments increase in abrasiveness to do commonly used piece of equipment for stone heavy scrubbing, texturing and even scarifying. refinishing. These machines can grind, hone, Soft nylon and natural hair pads of all different diamond polish, powder polish, clean, texture, grits and densities can be fitted on a standard or buff, depending on the accessory used. pad driver as well. These can be used to clean, scrub, strip, refinish, polish and hone stone 2.1.1 The speed and weight of the floors. machine can have a significant impact on the efficiency and quality of the 2.2 Planetary machines can be belt finished product. When only diamond or gear driven. They are much heavier than honing and refinishing, the optimal accessory is mono-rotary machines, making them ideal for a weighted drive plate. This adds grinding. They are usually reserved for large approximately 35 pounds (16 kg) to the residential and commercial jobs. They have a machine and speeds up the diamond honing pivoting head, which self‐levels as it goes over process. When grinding (also referred to as the floor. This allows the technician to push it lippage removal), weight should be added to like a lawnmower and not have to use his or her the machine to increase pressure and help body to swing the entire weight of the machine

 2016 Marble Institute of America Equipment• Page 21-27 around. The most common configuration is 17 pounds (16 kg) and normally requires 2 hands to 20-inch (430 to 510 mm) diameter with 3 to remove or install. satellite heads. 2.3.2 Lightweight drive plates. Nylon 2.2.1 Active and passive planetary or plastic drive plates are classified as machines. Active planetary machines have lightweight. This style is used for light-duty “driven” heads. The main head, which is the scrubbing and buffing and sometimes light large diameter, is driven by a belt or gear set. refinishing or polishing. Lightweight drive It is directly connected to the 3 planet heads plates only weigh a few pounds and are easy to and drives them continuously. Passive remove or install with one hand. The ease of planetary machines have non-driven heads. changing out the drive plate results in The main head is driven by a belt or gear set, significant time savings. and the planet heads are essentially free to rotate in the direction they are pushed. 3.0 HANDHELD MACHINES 2.2.2 Floating and Rigid Heads. Floating heads are ideal for concrete. The heads 3.1 Variable speed angle handheld are firmly attached to the machine, with rubber polishers come in multiple varieties. For grommets or a cushion in between. This allows restoration and refinishing, it is best to own a the heads to “float” over the highs and lows of variable speed polisher. The most commonly the floor, or over bad lippage on stone tile recommended variable handheld polisher is floors. These types of heads are almost always typically referred to as a 7-inch (180 mm) present on belt-driven machines to help absorb polisher. This polisher is designed to accept 7- the shock and keep the belt from slipping. inch (180 mm) grinding, honing, and polishing Rigid heads are bolted to the machine. They are abrasives. The 7-inch (180 mm) polisher is unforgiving and offer no flexibility. These are larger than the machine referred to as a usually found on gear driven machines that are grinder. The motor is larger and more built heavy duty use. Rigid heads are used with powerful. A 7-inch (180 mm) polisher usually the intention of planing down the stone floor features variable speed control. The ideal to a perfectly flat surface. Some planetary speeds start as low as 600 RPM. Most stone machines have the flexibility to switch between refinishing jobs can be completed under 1,000 the two head configurations by simply bolting RPM. The use of a slower speed creates less the desired set of heads on the machine. These mess. Some restoration technicians prefer the machines are preferred by many due to the 7-inch (180 mm) polisher because of the larger flexibility that they offer. motor so that they can apply additional pressure to the grinder by leaning on the 2.3 Drive plates: 10”, 17”, 22”, (250, machine without the motor stalling out. 430, 560 mm) and larger 3.2 Pad drivers: 3, 4, 5 and 7-inch (75, 2.3.1 Steel drive plates usually feature a 100, 125, and 180 mm). Pad drivers, also hook and loop attachment configuration on the referred to as backer pads, are the connection bottom that are used to attach various diamond between the tool and the abrasive. They attach and other abrasive pads. This style is designed to the angle grinder or polisher and provide a to withstand adding weight to the machine to surface or mechanism for attaching the give the abrasive more pressure and contact abrasive. They are available in several with the floor. Steel drive plates also feature a configurations. low center of gravity to speed up production. The plate usually weighs approximately 35 3.2.1 Rigid aluminum pad drivers are the most rigid type available and are ideal for

Page 21-28 • Equipment  2016 Marble Institute of America refinishing slab counters. A rigid abrasive and 4.0 ABRASIVES pad driver will help the technician achieve a flatter finished surface, which is closer to the 4.1 Abrasives are used to grind, original factory polish. hone, and polish stone for the purpose of restoring or refinishing. As stone 3.2.2 Rigid composite pad drivers have wears, it become necessary to remove light or the same features as aluminum pad drivers, but deep scratches, fill in voids or cracks with a have a tendency to lose their perfectly flat patching material, and sometimes taper a profile or warp after extended time in service. surface to improve a transition. Each of these processes requires the use of abrasives. For 3.2.3 Flexible pad drivers are made of scratch removal, the abrasive is used to grind hard rubber and will flex a moderate amount down the surrounding material to the same when under pressure. These are generally used plane as the low point of the scratch and for fabrication when there is a contour or shape continue using consecutively finer grit that needs to be polished. For restoration, abrasives until the original finish is matched. these are great for working in showers or on Voids or cracks are repaired with a patching tile countertops where rigid pad drivers might material. Abrasives are commonly used to cause the abrasive to bounce from tile to tile. smooth out the patched area and blend it to the same plane and finish as the surrounding stone. 3.2.4 Super flexible pad drivers are Transitions are needed when a stone floor is on made from soft rubber and can be bent with a higher plane than an adjacent floor or when minimal force. They are designed for extreme tiles have been installed with excessive lippage. contours. Many restoration technicians use these with dry abrasives for quick touch ups on 4.2 Silicon carbide and diamond are the edge of a low tile where it meets an the most commonly used abrasive types adjoining high tile. As with other flexible pad for stone refinishing and restoration. drivers, these can make quick work of shower Both are hard enough to abrade the hardest and tile countertop restoration because of the stone, but diamond, being the hardest natural ability to allow abrasives to make contact with substance in the world, will cut noticeably stone in low areas. Super flexible pad drivers faster when working with very hard stone can also be used in repairing and refinishing materials. The cost of most diamond abrasives complex edges on stone tops. is usually higher than silicon carbide. It is important, however, to include the costs of 3.2.5 Free spinning pad drivers are labor and machine hours in addition to abrasive relatively new to the industry. The main drive costs when estimating total actual cost. In some plate is aluminum and fits onto the arbor of the cases, a diamond abrasive may cut too fast for machine. It is surrounded by a second plate, the task. Keeping both types of abrasive in which acts as a shell, and is isolated by a bearing inventory is the solution that works best for in between the two. When the outside plate most companies. Either abrasive can be used hits glass, metal, or any other delicate surface, for the full range of refinishing or restoration it stops spinning, but allows the inner drive tasks. These abrasives are available in many plate with the abrasive attached to keep varieties as outlined in the following sections. spinning. These are convenient in showers and when working around metal and glass edges, 4.3 Bricks. 14 cm (5½”) bricks are used since they minimize potential damage to in a sweeping rotary motion instead of a adjacent materials. straight rotary motion. Because of the compound movement and features of most floor machines, 14 cm (5½”) abrasives are not used for refinishing and restoration. The most

 2016 Marble Institute of America Equipment• Page 21-29 common abrasive bricks for stone refinishing 4.3.3 Synthetic bond frankfurt and restoration are frankfurt segments. segments are similar to magnesite bond Frankfurt segments are a wedge-style brick segments, but made from synthetic material. designed to fit in to a wedge-shape shoe or This makes them similar to resin bond opening connected to a drive plate. Frankfurt abrasives. Synthetic bond abrasives can break bricks, often referred to as frankfurt segments, fairly easily, but not as easily as magnesite are available in multiple abrasive types and bond. Using more forgiving raw materials bonds. creates the increased stability over magnesite. When finishing MTL floors and terrazzo, the 4.3.1 Frankfurt does not relate to a synthetic tools will usually carry the finishing specific bond, but describes the shape process to the end and complete the final and size of an abrasive type. The abrasive preparation for the polishing step. are attached to the drive plate by wedging them into a holder (sometimes referred to as a shoe). 4.3.4 Hard synthetic bond frankfurt It is a widely recognized abrasive used on the segments are very hard and can be used on more traditional style grinding machines and concrete, granite, quartz, and quartzite slab polishers from Europe. Frankfurt abrasives surfaces. This abrasive bond is typically used are typically used on flat floors or terrazzo after regular synthetic abrasives and continued only, and are generally not used on tile floors to the end of surface preparation, or for hard with lippage present. Some designs allow the materials only. Using a hard synthetic bond abrasive to grind lippage flat. The brick-style frankfurt segment will produce clarity that is frankfurt segments are inexpensive and wear ready for polishing. out quickly, but provide phenomenal results. Onsite results with these segments is very close 4.3.5 Polishing and cleaning brick. The to that of the factory process. Because of their polishing (or cleaning) step is essentially an rigid design, there is absolutely no flexibility MTL (marble/limestone/travertine) polishing with these abrasives. This design ensures a high powder product compressed into a brick. quality finished product. The floor machines There are usually two products and steps designed for these frankfurt segments usually involved. The final frankfurt segment is usually are more complicated to operate than more made of pure oxalic acid. Many stone commonly found floor machines. processing factories use oxalic acid during the final polishing step. When viewing MTL slabs 4.3.2 Magnesite bond frankfurt in direct sunlight, faint swirl scratches can segments are typically used after sintered sometimes be detected. The swirl marks are a metal abrasives. They are structurally unstable result of the final step being performed with a and can break easily. The instability of this fixed abrasive and not a polishing powder. abrasive bond is two-fold. First, they are a poured brick abrasive, so dropping them will 4.4 Plugs are often referred to as terrazzo usually result in chipping or breaking. Second, plugs because they are commonly used during sometimes the mixture is not properly the initial grinding process for terrazzo. The prepared and the abrasives can shatter with the plugs are held in place using specially designed temperature change caused by getting them drive plates. Terrazzo plugs are usually made as wet. Magnesite abrasive bricks, whether a sintered metal bond diamond abrasive. frankfurt or another type, wear down very quickly compared to other bonds. They are 4.5 Abrasive pads are commonly effective in removing heavy scratches from the referred to as discs or wheels because of their lippage removal abrasives and leave a nice finish circular shape. Square or rectangular pads are for the next step. also available for sanding blocks and orbital style sanders. The most common shape is

Page 21-30 • Equipment  2016 Marble Institute of America round and the most common sizes are 3, 4 and from contamination from dirt or other foreign 5-inch (75, 100, and 125 mm). Pads are matter. available in multiple bonds using diamond or silicon carbide as the abrasive type. Different 4.5.2.1 Pros of synthetic fiber pads. manufacturers attempt to gain customer  Cost effective loyalty by using unique features like innovative  Easy to use bonds, grit size, segment design, tapered edges  Very flexible; allows the abrasive to and others. A sintered metal bond abrasive get in and out of low areas and lippage used for more aggressive cutting is normally referred to as a lippage removal pad. These  Work quickly aggressive discs are typically mechanically  Can achieve multiple levels of honed attached directly to the tool or drive plate floor finishes, and in some cases, polishes, machines and handheld polishers. If using a without leaving scratches or trailing handheld polisher to complete the outer edges marks of the floor near the walls, then a cup wheel would be used. A cup wheel is the handheld 4.5.2.2 Cons of synthetic fiber pads. equivalent to lippage discs for floor machines.  Cannot provide a flat for when used as For lighter pads, the hook and loop system a set (tend to texture the stone) usually works well and helps to speed up the  Will not remove moderate to heavy process of changing grits. Pads are the most scratches common abrasive variety.  Can get damaged easily on stone tiles with heavy lippage 4.5.1 Fiber pads are not typically used for heavy grinding: only for honing and polishing. 4.5.3 Dot pads. “Dot pad” is a generic They are circular in shape, but the sizes used name given to a certain type of fiber abrasive are typically much larger than the small 3, 4 or pad. These utilize a 17” (430 mm) synthetic 5-inch (75, 100, and 125 mm) abrasive pads fiber pad like described above but there are mentioned earlier. Fiber pads are woven, and resin dots or diamond abrasive embedded resin some manufacturers use this weave to hold or sections permanently affixed to them. This suspend abrasive powders. Other variety has an advantage over the plain manufacturers will lightly bond the woven pad synthetic fiber pads because they contain hard with abrasives. A major advantage of fiber pads resin dots, which allows them to work more is that they will conform to low areas of the quickly and provide a superior finish. floor to abrade the entire floor. This is one of the most common varieties for refinishing. 4.5.3.1 Pros of dot pads.

 Work quickly; provide a similar finish 4.5.2 Synthetic fiber pads are synthetic to traditional resin diamond pads buffing pads that have abrasive grit  incorporated into the pad. During the Easy to work with manufacturing process, these pads are sprayed  Flexible and easy to navigate through with an abrasive impregnated liquid lippage and other uneven areas compound. This process allows the mixture to  Does not need to be protected as much penetrate deep within the fibers of the pad. The as other synthetic fiber pads result is abrasive content throughout the pad, which extends the service life of the pad. The 4.5.3.2 Cons of dot pads. abrasive life of these pads is similar to that of a  Expensive when compared to thick resin diamond. When not in use, they traditional diamond abrasive pads should be stored properly to protect them  Fiber pad can get damaged before using the entire life of the pad  2016 Marble Institute of America Equipment• Page 21-31

4.6 Abrasive bonds. The bond used for 4.6.1.2 Semi-flexible. For stone refinishing the abrasive can vary based on the abrasive and restoration, semi‐flexible abrasive pads are type, grit, and task being performed. The bond the most common flexible abrasives. Thick or holds the abrasive in place until it is used up. thin, they all share a layer of foam or neoprene Depending on the task at hand and desired between the actual pad and the Velcro surface. finish, different types of abrasives and bonds This allows for some rigidity, but also some may be used. If the task is to remove heavy bend if the diamonds hit a sharp edge or uneven material stock, then a more durable bond and surface. If the flexibility is not there, the resin coarser abrasive is desired. If the task is to segments can break off. This type can be used simply clean the surface, then a lighter bond on anything from a perfectly flat floor to a floor and finer abrasive is desired. There are many with moderate lippage. The flexibility of these different sizes, shapes, and prices for abrasives. pads will allow them to act as shock absorbers With experience, each technician will develop and ride up over the uneven tiles. a preference for different tasks. 4.6.1.3 Flexible abrasive pads are the type 4.6.1 Resin bond abrasives are by far the most commonly used in stone fabrication most commonly used and most widely shops, in 3” to 5” (75 to 125 mm) diameter. recognized type. They are available in several These are used on handheld machines to polish shapes and sizes. Resin bond abrasives can start edges and tops of counters and other stone as low as 30-grit and go as high as 8,500-grit. applications. Their flexibility allows the This type is most commonly used for light fabricator to avoid angling off a convex edge refinishing to remove minor scratches, etch detail. A few companies make these in 3” (75 marks and to prepare for a honed or polished mm) diameter, which can be used on a floor finish. Resin abrasives are produced in bonds machine. Foam risers almost always specific for different stones and hardness. The accompany this type of abrasive. The risers are general rule is that a soft resin is used for hard very forgiving; almost spongy. They attach stones and a hard resin is used for soft stones. directly to the drive plate, and the abrasive If a soft-bonded granite resin abrasive is used pads attach to the riser, adding flexibility. This on marble, it will wear at an accelerated rate. setup is used on floors with light to moderate The same scenario applies for using marble lippage. The weight of the machine will abrasives on granite. The resin needs to wear at compress the riser, allowing the edge of the the correct ratio in order to allow exposure to pad to flex or curl slightly. This setup ensures the diamond abrasive without causing the resin that the abrasive reaches the low areas of the to form a coating over the abrasive. Soft stone uneven tiles and help to eliminate picture attacks the soft bond in the abrasives, causing framing.1 the bond to wear faster and lose diamond or abrasive particles. Resin bond abrasives come 4.6.2 Marble bond resin diamond in rigid, semi‐flexible, and flexible variations. abrasive pads are designed specifically to be used on MTL surfaces. Marble abrasive pads 4.6.1.1 Rigid, puck style abrasives are can be used on these floor types, although some usually used for flat floors. This type is also manufacturers produce pads specifically for used after a floor has been ground flat, like in each type. As mentioned previously in this lippage removal. The rigid style will limit the chapter, a hard resin is more effective for soft amount of fluctuation in the flat appearance of stones like MTLs. Although not usually the finished product by not allowing the tools recommended, marble abrasives can also be to flex and dig into the stone. used for concrete polishing. Many marble bond

1 “Picture framing” is a term used in the stone section of a tile are not abraded when working restoration industry meaning that the low on a floor that is not completely flat. Page 21-32 • Equipment  2016 Marble Institute of America abrasives will work quite well and provide grinding, also referred to as lippage or severe reasonable service life when used on damage removal. They do the most work, take residential‐type concrete. Other abrasives the most abuse, and produce the quickest suited for concrete will be discussed results. Metal bond abrasives are mainly used throughout this chapter. for removing heavy scratches. They can also be used to remove chemical damage on terrazzo 4.6.3 Granite bond resin diamond and concrete, remove lippage from uneven abrasive pads are designed to achieve the tiles, or remove a sizable amount of material. highest possible clarity before the final There are several different types of metal polishing step. Granite is very hard compared bonds that serve different purposes. Some of to MTL stones, so time becomes a factor. The these are as thin as 1 mm (0.040”) and are higher quality the granite resin pad, the faster available up to 12 mm (½”). Metal bond you will get to the polishing step. Also, the abrasives can start as low as 6-grit and go all the better quality finish the resin pads achieve, the way up to 1200-grit. The bond can greatly less work is needed on the final polishing step. affect the finish. A metal bond 200-grit abrasive Due to the methods by which they are is much more aggressive than a resin bond 200- produced, higher quality abrasives will grit abrasive. To remove the scratch pattern of typically result in a premium price. a metal bond abrasive quickly, it is necessary to use a much lower grit resin bond abrasive. 4.6.4 Phenolic bond resin diamond abrasive pads are used to withstand heat and 4.6.7 Sintered bond. Sintering is one of friction. These abrasives are usually used for the most commonly used methods for dry honing and polishing. Because of the heat assembling diamond abrasives in our industry. generated from the friction during this process, Bridge saw blades and most grinder blades use the resin was designed to withstand the a sintered metal bond. When inspected closely, temperature without burning or glazing over. small diamond segments protruding from the Most other abrasive bonds are damaged when metal surface can be seen, often with exposed to the same conditions. Phenolic directional streaks trailing them. These appear resins are made mostly for concrete and are almost like a comet and a tail. Sintering classified as a resin or a resin‐hybrid pad. assembles abrasives in a manner that holds the diamonds within the body of the segment. As 4.6.5 Hybrid bond diamond abrasive the abrasive or segment is used, the metal pads are relatively new. These utilize a wears away, exposing new edges of the traditional resin mixed with a soft metal like diamonds. This can be compared to a self- copper to create a pad that is extremely sharpening blade. However, if the metal used effective and forgiving. They are designed to for the bond and the stone are not compatible, remove material quickly and leave a smooth the metal will glaze over the diamond. It will finish, so the next finer grit is easier essentially cover the diamond and slow down transitioned. Hybrid pads can be used as the process until it can be dressed to expose the transition pads when working your way out of diamond or cutting abrasive. This bond type is the metal grinding stages into the resin honing designed for rapid removal of stone. It will stage. Hybrid bond abrasives will remove the leave moderate to heavy scratches compared to heavy scratches of the metal lippage discs and other bonds. The most common application in leave a finish smooth enough to be picked up the restoration industry for this bond is for by the next resin step. They are a very helpful lippage removal. Because of the materials used addition to the toolbox. to make the sintered discs, they are the usually the most expensive, but also have the longest 4.6.6 Metal bond diamond abrasives life span. Terrazzo plugs are made of sintered are heavy duty and used for coarse or initial segments.

 2016 Marble Institute of America Equipment• Page 21-33

4.6.8 Copper bond. Copper diamond electroplated abrasives are extremely abrasive pads are also sintered, but significantly aggressive, but leave a much smoother finish different. They are made with a softer lighter when compared grit‐to‐grit. They can be used copper material as opposed to the heavier for quick repairs of heavily damaged material metal that is used for standard sintered tools. or as a transitional grit between sintered and This bond is not recommended for the initial resin abrasives. These abrasives can be used step in lippage removal because it will wear wet or dry, and excel on MTL stones. It is also down very quickly and will not cut as fast. The possible to use them on concrete. However, copper bond was developed as a transitional electroplated bond abrasives do not hold up bond to bridge the gap between metal and resin through use on harder stones, such as granite. bonds. They offer the best of both worlds: heavy scratch removal while leaving a smooth finish to facilitate the transition into the resin 5.0 POLISHING COMPOUNDS steps. Copper bonds work well for cleaning up traffic worn or chemically damaged surfaces to 5.1 Marble polishing powders have prepare for refinishing. Copper bond discs are revolutionized the refinishing and restoration a “must‐have” for the toolbox. industry by increasing production and improving quality. There are so many marble 4.6.9 Vacuum brazed diamond polishing powders on the market today it can abrasives are the most aggressive metals used be difficult to distinguish individual products. for floor refinishing. This type of bond abrasive There are “hot” powders, “cold” powders, and will cut very fast and leave heavy scratch many in between. For the purpose of this marks. Unlike sintered diamond bonds, discussion, “hot” or “cold” refers not to vacuum brazed abrasives are attached to the temperature, but to acid content. Acids found outermost surface, exposing all the diamonds in marble polishing powders vary, but a hot on the face. This bond does not have the life powder contains a higher percentage of acid. span of sintered metals, but is less expensive. These tend to polish more quickly, but the When the goal is to remove material as fast as technician risks over-use, which can result in a possible, vacuum brazed is the normally the poor finish. Overuse of hot powders will result best choice. Because of their aggressive nature, in an orange peel look on the stone. Cold they are not typically used on MTLs. Vacuum powders have a lower acid content and take a brazed diamonds are much thinner and lighter little more time to work, but they provide than sintered discs and will most likely have a better protection against overuse. Most convex shape to the face to allow for a smooth polishing powders on the market work to some transition over uneven tiles. extent on most marbles. However, some marble will react differently and require the 4.6.10 Electroplated bonds are similar to use of a different mix of acids. Each technician vacuum brazed bond abrasives in appearance. will develop the sense of what mixture is These bonds are easily mistaken for each other. needed. Electroplating is a coating, while vacuum brazing is a type of weld attachment. 5.1.1 Types of marble polishing Electroplated diamonds are the thinnest in the powders metal group at 1 to 2mm thick (0.040 to 0.080”). The diamonds appear to be on the 5.1.1.1 Wet polishing powders are surface like brazed metals, but are attached designed to be used with water. Water is added through a different process. Electroplated and worked into an area to generate a slurry. bond abrasives are the least expensive of the The polishing process is completed while the metal group and also have the shortest lifespan. mixture is still wet, then the slurry is removed Similar to vacuum brazed abrasives, with a wet vacuum.

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5.1.1.2 Wet-to-dry polishing powders 5.1.3 Characteristics of polishing are usually very “hot,” meaning that they powders. Polishing powders vary contain a lot of acid and work very quickly. significantly among products. The amount of Using this type of polishing powder means that water and pads used, speed and weight of the the process is started either in a wet slurry, or machine (including weights added), and how with just a mist of water and worked until long each section is polished all have an impact completely dry. The technician will get a feel on the final polish. for how much water is needed through experience. It is better to achieve the polish in 5.1.3.1 The amount of water used can stages than to risk over-polishing the stone and make the biggest difference when polishing. resulting in an orange peel appearance. Using Using less water creates a more concentrated, wet-to-dry powders eliminates the need to or potent, powder. Using more water will vacuum after polishing each section. This dilute the powder, making it less effective. process requires the use of more heavy-duty “Hotter” (more acidic) powders can be diluted machinery, because of the significant friction down more for sensitive stones. Using too produced during their use. much powder and not enough water will damage the stone’s finish. 5.1.2 Ingredients for marble polishing powders. MTLs are calcium-carbonate based 5.1.3.2 Type of pad. The two major types of stones that react to most acids. Every marble pads are white nylon polishing pads and hog’s polishing powder includes an acid and an hair polishing pads. abrasive, along with other proprietary ingredients. 5.1.3.2.1 White nylon polishing pads are dense and soft to the touch, with multiple 5.1.2.1 Oxalic acid breaks down the surface fibers intertwined into the same area. Due to of the stone to allow the abrasives to do the their density, they tend to hold more of the work. It activates when water is added. polishing compound on the immediate surface. This allows the compound to do all the work. 5.1.2.2 Shellac is a type of resin that naturally There are pros and cons of this, depending on occurs on trees. It is pulverized into a powder what type of stone is being worked on and what and added to the compound. The heat created type of equipment is being used. by the friction from the polishing process melts the resin and deposits it into the micro-pores of 5.1.3.2.2 Hog’s hair polishing pads are the stone. It hardens immediately after cooling much coarser and less dense than white nylon and helps give the floor a more uniform look polishing pads. The fibers are a mix of natural and increases gloss. boar and synthetic. The fibers are thicker and Shellac is not often used in more recent the pad is less dense. Due to the lack of density, powders to enter the market. more of the polish is absorbed by the pad, leaving less on the contact surface. This adds a 5.1.2.3 Aluminum oxide is a new dimension to the polishing process. manufactured, inert powder. It is a pure abrasive and is used to achieve final polish. It is 5.1.3.3 The amount of weight needed considered a super fine grit, although it is depends on the material more than the unclear just how fine it is, and works to smooth powder. Some materials “burn” easier than out the surface of the stone while it is in a others. It is very similar to polishing vulnerable state from the oxalic acid. automotive paint. The harder you push, the Aluminum oxide is harder than granite. more friction is generated. Friction translates to heat and can orange peel—leaving a textured look to the finish. The experienced

 2016 Marble Institute of America Equipment• Page 21-35 technician will get a feeling for when adding abrasive and a mild acid which do not coat the weight is needed. material but act more like a super fine abrasive to enhance the reflective finish of the stone. 5.1.3.4 Speed has essentially the same effect as weight. More speed equals more friction, 5.4 Honing powders can be used either which in turn makes more heat. Increased for minor damage removal or finishing. Most speed also makes more mess, causing the slurry honing powders are between 120 and 800 grit, to travel further. depending on the manufacturer. Honing powders are made from aluminum oxide. 5.1.3.5 Time. How long each section is These powders are used with water to create a worked with a polishing powder can have a slurry and are used to put a final honed finish very big impact on the quality of the final on almost any material. Usually the stone will polish. On marble, working a section too long be refinished or the polish will be broken with with an acidic polishing powder can cause diamond abrasives, then the honing powder orange peel or etching. It is better to perform will be used as a final step. Because the powder this task in stages until the technician is familiar is loose, as opposed to a fixed abrasive, it leaves with the reaction between the polishing no detectable swirls or tool marks. powder and the marble. For granite, the overuse of polishing powders is not usually a problem, although it can leave the stone hazy 6.0 ADDITIONAL TOOLS AND or dull. SUPPLIES

5.2 Polishing pastes are usually 6.1 Miscellaneous honing/polishing polishing powders in a paste form. They are pads used with compounds and already “active,” containing their own liquid. powders. Steel wool pads are used mostly Water can be added if the paste dries out or if when crystallizing. Champagne pads are used a more diluted slurry is desired. Pastes are for honing and/or polishing. Black pads are generally grittier than powders. The grit or used for stripping coatings. Tampico brushes chunks that can be seen and felt are oxalic acid are used for polishing. chunks. These get absorbed into the polishing pad and act to further polish the material. 6.2 Cleaners Although it may feel like the paste will scratch the stone, it has no effect on the finished 6.2.1 Neutral cleaners have a pH of 7. product. Oxalic acid is water-soluble and They are neither acidic nor alkaline. Neutral slowly dissolves while being used. cleaners are used for light washing, rinsing, cleaning and neutralizing after polishing or 5.3 Liquid polishes, also known as using an acid based cleaner. Homeowners are crystallizers, are misted on the surface and advised to use these. buffed with a mono-rotary machine with heavy weight and a steel wool pad until dry. The 6.2.2 Alkaline cleaners are at the top of liquid provides a chemical bond with the stone. the pH scale, with a pH typically between 12 The steel wool heats up the liquid and surface and 14, depending on the manufacturer. and allows it to harden as it fills in the scratches Cleaners with a pH between 13 and 14 pH can and pores of the stone. This process is used damage polished MTL floors if not correctly mostly in commercial maintenance settings, diluted. This type of cleaner is usually used as a although it is not designed to be a maintenance degreaser or to clean heavily soiled floors and product. Liquid polishes work differently than grout. Alkaline cleaners are generally good at polishing powders and pastes. Polishing breaking down soap scum and weak waxes. powders and pastes usually contain a fine

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They can also be used to neutralize acidic stone. Most grits feature thicker, stiffer rubber cleaners. bristles designed to reach most areas, but not the lowest sections of the stone. Higher grits 6.2.3 Acidic cleaners are only used on feature larger, wider rubber bristles designed natural stone when absolutely necessary and to skim across only the top sections of the should be avoided inside the home if possible. texture. The larger, wider bristles are designed Most acidic cleaners usually have a pH between to put a shine on the peaks of the texture. 4 and 2, depending on the acid used. The most common acids used are phosphoric, 6.4.3 Carbide bristle brushes are made hydrochloric and sulfuric. These cleaners are using silicon carbide abrasives. Thin, wiry usually used for removing mineral and hard bristles are impregnated with the abrasive. water deposits, cleaning excessively dirty Carbide bristle brushes can be used for grout, and removing rust stains. Only use antiquing, light texturing, or just for scrubbing acidic cleaners when other options have been rough surfaces. exhausted.

6.3 Wet/dry vacuums perform a very necessary function. It would be difficult to refinish or restore stone without the ability to remove the dirt and debris or slurry created that could interfere with honing and polishing.

6.4 Antiquing Brushes. Antique finishes have become popular in recent years. The brushes used to achieve this finish come in several configurations. Antique finishes are usually presented in a matte or non-reflective range. When a more reflective finish is desired, each progressive grit will not reach as far into the lower areas of the stone. This results in only the highest points of the stone having a shine, giving it an antiqued or worn look.

6.4.1 Diamond wire brushes are by far the most aggressive. These brushes are made of relatively thick, hard bristles impregnated with diamond abrasives. Diamond wire brushes usually start at 36-grit and go up to 600-grit. They are usually used to remove the polish from granite and give it the initial antiqued or textured finish.

6.4.2 Rubber bristle brushes are produced featuring several different thicknesses and layers of bristles. There are different bristles and features designed for different grits. Lower grits will typically have very thin, concentrated bristles, typically used to reach the softer, lower textured areas of the

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NOTES:

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Restoration and maintain. Post-installation repairs will be the primary focus of this section. Maintenance – REPAIRS 2.0 PRODUCTS AND SUPPLIES

1.0 INTRODUCTION 2.1 Adhesives and Patching Materials. Before beginning the discussion of 1.1 Repairing stone is a normal part of techniques, patching material selection will be restoration. Many stones, especially very discussed. No matter how good a repair looks decorative varieties, have natural voids and cosmetically, if the wrong material was used it weaknesses. Filling these voids and reinforcing will not perform and must be redone. The these weaknesses is normally started early in most reliable product must be used to ensure the processing phase at the factory level. The the longevity of the repair. material is quarried in a block form; it is then transported to a factory for processing into 2.1.1 Adhesives and patching materials are useable products such as slabs or tile. After used to adhere broken pieces back together cutting these blocks into slabs, many materials (also known as “sticking”), fill pits or voids are filled, repaired, or reinforced using a (either natural or created by movement) and variety of methods. Once the initial repair or reinforce weaker areas of the stone. The reinforcement is done, the product is ground materials that are most common in the stone down to start the finishing process. After the industry are polyester, acrylic, epoxy, initial grinding step, it is sometimes necessary urethane and cyanoacrylate (also known as to touch up the repair before proceeding to “CA”). finalize the desired finish for the stone. 2.1.2 Most of these materials are available in 1.2 Many installers will cull pieces from different viscosities for different applications. the lot during installation. In some cases, the When trying to penetrate micro-fissures, the quantity ordered is insufficient if extensive least viscous or thinnest product would be culling is required. The bid process can be very selected for this task. Many manufacturers competitive, so extra pieces are a luxury that refer to this as a “penetrant” or “super cannot always be afforded in order to win the penetrant.” For sticking loose pieces of stone bid. After installation, the existing repairs may together, a slightly thicker product would need to be retouched. Often, the processing typically be used. This product is often referred factory performs a generic repair that may to as “flowing.” Filling holes and voids would work in some areas of the stone but is very require thickest product. Most manufacturers noticeable in other areas. The factory doesn’t call this a “knife grade.” Many of the products always know the intended application of the are two-part. Part one is typically referred to product when they are producing it, so as the adhesive or resin and part two is typically sometimes an inappropriate patching material referred to as the catalyst, hardener or curing is used (for example a polyester resin when the agent. One product category requires no material will be used for an exterior curing agent because the curing process is application). In that case, the patch needs to be activated by exposure to air. Each product removed and replaced with a more suitable category will be discussed in further detail patching material. Other times repairs need to throughout the section. be made due to everyday use, faulty installation products or methods, structure settlement or 2.2 Colors and tints can be added to movement, and occasionally abuse or failure to adhesives and patching materials to provide a better cosmetic blend between the repair and

 2016 Marble Institute of America Repairs • Page 21-39 the surrounding stone. Follow the VOC value is being referenced and how the manufacturer’s recommendation for use. measurement should be taken. Be sure to Generally, if the missing sections of stone can allow for proper ventilation and use the correct be adhered back in to place, it will be a better Personal Protective Equipment (PPE) while repair than if patching material is substituted using adhesives or patching materials. for the missing stone.

2.3 The basics of adhesives and patching 3.0 CHARACTERISTICS OF materials are the same. One main difference is ADHESIVES AND PATCHING that most fast curing two-part products are MATERIALS mixed with colors or tints before the curing agent is added. Resin and curing agent for 3.1 Similar characteristics exist among the slower curing two-part products are often available adhesives and patching materials, mixed together before the color is added. although each variety has some distinct features There can be differences even within adhesive which are described below. categories because different manufacturers may use different ingredients to provide unique 3.2 Polyesters. benefits. It is very important in any two-part product to mix the products according to the 3.2.1 Polyesters resins are, at this time, the manufacturer’s instructions. most popular patching material used in the stone industry. Some of the reasons for this 2.3.1 CA glue. There is only one product popularity are assumed to be modest cost, listed below that is not categorized as a two- rapid cure time, bond strength and familiarity part adhesive or patching material. It is in working with the material. commonly known in the industry as CA glue or cyanoacrylate. This product can be used with 3.2.2 Polyester based adhesives are fast an accelerating agent. The use of accelerators curing, two-part products, so colors or tints can expedite the already fast curing time. If can be added to the resin before the hardener using an accelerator, do not use an excessive to achieve a visually better repair. amount on lightly colored stones. Overuse of accelerators is a common cause of staining in 3.2.3 Using more catalyst can accelerate the these stones. Accelerators are not necessary cure rate, but there is a risk of a weaker and for the adhesive to cure. It is important to be more brittle bond. The manufacturer’s familiar with the products before using instructions for mixing should be followed something that may cause additional problems. closely for best performance.

2.3.2 Volatile Organic Compounds 3.2.4 Polyester adhesives are commonly (VOCs) can have a big impact on the selection used in countertop seams because movement of the material to be used for a repair. VOCs usually results only in a failure in the adhesive are typically measured in two main ways. without damage to the stone. VOCs as supplied is the measurement right out of the container. This value is typically higher 3.2.5 Polyester resin can be sanded and because of the product concentration in the polished to a reasonably high shine, allowing it container. VOCs as applied is the to better blend with polished stone. measurement upon activation of the product. Once the product is activated the VOCs get 3.3 Acrylics. consumed and there are fewer emitted in to the air. For projects requiring VOCs below a 3.3.1 Acrylics became popular for use as certain value it is important to know which penetrants and are considered among the least

Page 21-40 • Repairs  2016 Marble Institute of America viscous among the categories. Penetrants are produces heat. Because of this, repairs commonly used to penetrate micro-fissures or requiring large amounts of adhesive may have very minute openings. Fissures are natural to be done in steps to prevent excessive heat separations in stone and are very common generation. among the most decorative varieties of natural stone. The next feature that helped this 3.4.6 Epoxies are available in multiple category gain popularity was the availability as viscosities: from penetrants to knife grade. a “water-clear” product. Many repairs are made better when the repair is “water-clear.” 3.5 Urethane.

3.3.2 Curing agents are typically used on 3.5.1 Urethane adhesives are the newest acrylics, and are usually liquid. This is done to class of stone adhesives. The price of this keep the product clearer and less viscous. category is relatively high. Urethane was developed to fill the gaps of the other product 3.3.3 Acrylics can be sanded and polished to categories. Urethane has excellent clarity and a reasonably high shine, allowing it to better its bond strength is close to the strength of blend with polished stone. epoxies.

3.4 Epoxy. 3.5.2 Urethane is a slow cure, two-part adhesives. Using an accelerator can speed up 3.4.1 Epoxies became popular because of the cure rate without the risk of a weaker or their superior bond strength when compared more brittle bond. Follow the manufacturer’s to other adhesives categories. Many people instructions for mixing for best performance. hesitate to use epoxies in some situations because of their lengthy cure time and 3.5.3 Urethane is used for many projects, increased cost. Epoxy is most associated for including patching or filling voids in stone and causing stains when used with white marble. bonding pieces of stone together. Urethane is Epoxies are most commonly mixed with other also used as a caulk-like material for expansion categories to make hybrid adhesives. joints and exterior joints.

3.4.2 Staining can be a problem when using 3.5.4 The stone must be dry before using epoxy with white marble or other light colored urethane adhesives, but this product can porous stone. Be careful to test any adhesive withstand exposure to moisture after curing. for use with light colored marble, limestone and granite. 3.5.5 The mixing ratio and thorough mixing are both critical to ensure complete 3.4.3 UV exposure can attack the look of polymerization when using urethanes. epoxies, but the strength of bond is relatively unaffected. This makes it one of the few 3.6 Cyanoacrylate (CA) glues. products that can be suitable for exterior applications. 3.6.1 CA glues are gaining popularity in the stone industry because of the different 3.4.4 The high strength and ductile viscosities available and the rapid cure time. properties of epoxy make it the preferred CA glues are typically sold in small units adhesive for use in structurally significant because of their relatively short shelf life. They roles. are often used to fill voids and micro-fissures. Because it is a fast curing product that rapidly 3.4.5 The curing of an epoxy is an cures when exposed to air, most professionals exothermic chemical reaction, meaning it tint the stone prior to applying CA glue.

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3.6.2 CA glue should not be used to bond 3.8.2 Polyester, acrylic, and some hybrids pieces of stone together. CA glues do not bond can typically share coloring systems. Epoxies as well as other categories. and urethanes usually require their own specific coloring systems depending on the 3.6.3 The use of an accelerator can cause manufacturer. staining if overused on lighter, more absorbent stones. 3.8.3 Urethanes are unique from the rest of the adhesive categories. Many do not cure into 3.6.4 CA glues are ideal for quick and easy a hard, polishable surface. Typically urethanes repairs. They are suitable for UV exposure and remain like a hard rubber, to allow for outdoor environments. They can also be used expansion and contraction. for seams in countertops because movement usually results only in a failure in the adhesive 3.8.4 For adhesives that require very and less damage to the stone. accurate mixing ratios, most manufacturers will list the required component ratio both by 3.7 Hybrids. volume and by weight (mass). Accurate digital scales can be readily obtained at a modest cost, 3.7.1 Hybrids have been developed by many and it is recommended to measure these adhesive manufacturers in an attempt to reduce components by weight (mass) as this method is the price of some adhesives and expand the more accurate than measurement by volume. benefits of others. A polyester/epoxy hybrid, referred to as a poly/epoxy, is the most 3.8.5 In the table at the end of this section, popular hybrid. each product category is compared by its typical features. These features are listed at the 3.7.2 Poly/epoxy hybrids have a stronger top of the chart and the product categories are bond than polyester adhesives. The cure time listed in the far left. is shortened when compared to epoxy adhesives. As with polyesters, the cure time of poly/epoxy hybrids can be adjusted. 4.0 COLORS AND TINTS

3.7.3 Poly/epoxy hybrids are more flexible 4.1 Coloring powders, pastes, and liquids than polyester adhesives. The mixing ratio is can be product specific, meaning there can be not as critical with poly/epoxy hybrids as it is different color products made for polyester, with epoxy. acrylic, and hybrids than for epoxy and urethanes. Some tints are more UV sensitive 3.7.4 Structural movement usually causes than others. Check with the manufacturer to be failure in the adhesive, so poly/epoxy hybrids sure the right tint for the adhesive and are considered suitable for countertop seams. application is used. They are also used for countertop laminations, mitered drop edges, and rodding or doweling. 4.2 When the right color is chosen, a repair will be visually undetectable. It takes 3.8 General notes about adhesives practice and patience to find the right color. and patching materials. For some materials, like white marbles, it is better to have a semi-translucent mixture with 3.8.1 Polyester, acrylic, and poly/epoxy just a hint of the correct shade of white. For require less hardener (usually in a ratio of 1% other materials, a water-clear mixture works to 4% hardener by volume) or curing agent best. Attention should be paid to the specific than epoxy. The typical mixing ratio for epoxy shade in the area of needed repair. The color is either 2 to1 or 1 to1 resin to curing agent. should be tested on a small area of the stone to

Page 21-42 • Repairs  2016 Marble Institute of America analyze the color match. If the patching used for the initial application process. material is a fast cure adhesive, the curing agent Afterwards, a putty knife or other spreading should not be added until the color is finalized. tool can be used. For thicker consistencies, a Sometimes the curing agent will change the paint spatula, putty knife, or mixing stick will color, so it is important to anticipate that and work. Afterwards, straight edge razor blades adjust for it. If the patching material is a slow are mainly used to smooth out the mixture. cure adhesive, then there is usually time to make adjustments. For multi-colored 5.7 Finishing tools typically include materials, it may be necessary to use multiple razor blades, steel wool, and chemical shades and to repair in sections. solvents.

4.3 Translucent stones, such as onyx, will 5.8 Grinding, honing, and polishing oftentimes be difficult or impossible to patch tools are die grinders, right angle with perfect cosmetic results. This is due to the grinders/polishers, diamond blades/grinding difference in light transmission within the stone wheels, diamond bits, masonry bits, 3, 4, and fabric versus that of the patch. 5-inch pad drivers (also known as backer pads), sandpaper (typically silicon carbide), and other abrasives (including antiquing brushes for 5.0 TOOLS textured finishes).

5.1 Tools used for repairs may vary slightly, depending on the personal preferences 6.0 REPAIRS of the technician. Despite this, the uses are universal. 6.1 Inspection. Performing a thorough inspection during the diagnostic phase of a 5.2 Personal Protective Equipment project will allow the technician to discover (PPE). This includes gloves, vapor masks, dust which repairs are necessary to help prevent masks, goggles, and other equipment as further deterioration of the stone. Many times recommended by the adhesive, abrasive, or the repairs will be natural voids or previous tool manufacturer. repairs that just need a touch up. Occasionally, repairs will be necessary because of structural 5.3 Cleaning tools include vacuums, movement or some other form of failure. acetone, denatured alcohol, stone soap, intensive cleaners, razor blades, super fine 6.2 Types of Damage. It is helpful to steel wool, soft bristle brushes, rags, determine what caused the damage so that compressed air, and other items as changes can be made to help minimize the recommended by the manufacturers. chances for reoccurrence.

5.4 Dispensing tools can be a pump, 6.2.1 Upward Crack. If one or two measuring cup, small capacity digital scale, isolated tiles are involved, then the most putty knife, or anything similar. probable cause is that the installer left a void under those tiles. Foot traffic, carts and other 5.5 Mixing tools can be a paint spatula, weight place on top of the damaged tiles putty knife, mixing stick, or anything similar. exerted enough pressure on the unsupported Thorough mixing is necessary when adding section of the tile to cause it to crack. This is color or curing agent to resin. the classic example of an upward crack. In an upward crack, two sections of the tile are 5.6 Spreading devices/tools. If the broken at an angle that has its high peak at the material is in liquid form, a spout is typically crack itself.

 2016 Marble Institute of America Repairs • Page 21-43

6.2.2 Inward or Downward Crack. area (or areas) can be fixed by injecting latex Structural movement will typically cause adhesive or a two-part epoxy to fill the void. damage to multiple tiles in a line that After injecting the adhesive apply weight to the sometimes crack in an inward or downward repaired areas and allow it to cure overnight or angle. This line can be somewhat straight or it longer as recommended by the manufacturer. may move to one side slightly to seek out the It is recommended to start these repairs a weakest point of the stone. This is known in the couple of days before you refinish the floor. industry as an inward or downward crack or After the tiles are secure, regrouting can be indent fracture. These are mostly caused by the done to finish the repair. settlement of the floor and where the crack itself is at the lowest point of the tile. 7.1.3 Downward Cracks should not be repaired, because this can make them more 6.2.3 Outward Crack. A crack in the sub noticeable. Most of the time such cracks are floor, or the joint of two pieces of cementitious barely visible, because they only appear as an backerboard under the tiles, can be either interruption of the light reflecting on the upward, or simply a slight separation of the cracked tile. However, if the crack can be felt tiles called an outward crack. An outward with the fingertips and is visible, it can crack is a slight gap caused by a separation of sometimes be disguised by flattening it out. To the stone. Both pieces of the stone are typically flatten an indent fracture, use fine grit on the same plane. sandpaper (such as a 220 grit) and sand the hairline crack flat. Be careful not to create a dip 6.2.4 Chips are typically missing sections of by keeping the angle grinder flat. If the surface stone that is usually the result of an impact is being polished, it can be cleaned out and from a dropped object. Sometimes, as a result filled with penetrating adhesive to repair it and of a crack that splits, small sections of the stone keep it clean during the process. will become dislodged and swept or vacuumed up and discarded. This creates a larger gap to 7.1.4 Outward Cracks involve several be filled. tiles in a row and can be repaired. It is important to inform the client that there is structural movement involved, so no guarantee 7.0 REPAIR SUGGESTIONS can be given that it will not crack again. If the crack reoccurs, a better solution would be to 7.1 Crack Repair. install an expansion joint or a crack isolation membrane. Both of these remedies require that 7.1.2 For upward cracks, the first step is the stone tile be removed in order to make the to determine is if any of the two (or more) corrections. It is very difficult to match existing parts of the cracked tile(s) are solid, or if they stone unless the client kept extra pieces from are slightly moving. In nearly all cases, the the same lot. grout of a tile cracked upward has separated and become dislodged. It must be determined 7.2 Chips. For the best repair, some of if there is enough room between the tiles the stone should be glued back in to place. If (grout gap) to allow grout to be fully pushed the chip was discarded and there are no extra in. If the section of grout is not deep enough to pieces of stone available, then filling the void hold more grout, then more of the old grout with an adhesive, as a patching material, is may need to be removed. Before regrouting, needed. It is necessary to clean the damaged check to see if either section of the broken tiles area thoroughly before applying the adhesive. is loose. If there is no longer a bond between Once the patch has been made and cured the the tile and the subfloor, tapping the surface grinding and honing process can begin. To will produce hollow sounds. The unbonded verify that the patch will blend, check the patch

Page 21-44 • Repairs  2016 Marble Institute of America by wetting the area after grinding the section 8.2 Fixing micro-cracks and flat and before finishing the honing and separations using a penetrating polishing process. adhesive.

8.2.1 Before beginning repairs, consult the 8.0 REPAIR TECHNIQUES product’s SDS to determine if PPE is necessary for the task. Begin by cleaning and drying the 8.1 Preparation. The crack must first be stone thoroughly. prepared, and the appropriate filler must be determined. Vacuums and die grinders with an 8.2.2 Use a torch to warm the stone until it assortment of bits and blades are the most is warm, but not hot, to the touch. Do not use commonly used tools for crack preparation. a flame near acetone or other solvents. The die grinder is used to dress up or enlarge the opening as necessary to ensure proper 8.2.3 To minimize the risk of a large stain, it filling. If repairing a broken corner of a tile that is best to mask off the stone with tape. Leave is loose but still in place, it is best to proceed only a narrow opening (approximately 1/8” or by removing the broken piece and cleaning the 1/16” [3 or 1.5 mm] beyond the separation on edges of the tile and the removed piece with a each side) on the pieces needing repair. die grinder and abrasive bit. Afterwards, the corner should be dry-fitted in place to ensure 8.2.4 Mix the penetrant according to the that it is finished at the same plane as the rest of directions supplied by the manufacturer and the stone. If it is high, continue to clean the add color if desired. void until it is almost flush. If it is low, fill the hole where the broken piece was with color- 8.2.5 Pour and spread the adhesive into the matching knife grade adhesive or a mixture of crack. Allow the adhesive to penetrate the knife grade and flowing adhesive. Set the stone. The time span necessary will depend on broken piece back into place by pushing it the curing time of the adhesive. Allow the against the broken tile and as flush as possible adhesive to cure for the time recommended by with it. It is better to leave the corner very the manufacturer. slightly raised rather than depressed. Once the repair is cured, grinding it until it is flush with 8.2.6 After the adhesive has cured, use a the rest of the stone can flatten the corner out. razor blade to remove the tape and any excess adhesive from the face of the stone. If this is 8.1.1 The consistency of the repair done before the adhesive is fully cured, leave adhesive necessary will depend on the type the excess adhesive to allow for shrinkage. of crack being repaired. For general crack repairs, use knife grade adhesive and push the 8.2.7 Grind, hone, and polish the stone as adhesive into the void with a spreading tool necessary to complete the repair. such as a razor blade. It is best on fast cure two- part adhesives to mix the adhesive with the 8.3 Fixing macro-cracks and intended colors without adding curing agent separations using flowing and knife until the client approves the mix. For grade adhesive. adhesives known to shrink, it is necessary to apply excess adhesive to allow for shrinkage. 8.3.1 Consult the material’s SDS to Consider the finished appearance of the determine if PPE is necessary before beginning adhesive before using it on honed or textured repair. Begin by using a razor blade to remove materials. loose pieces or existing fill from the crack. Clean all sections to be filled and allow the stone to dry thoroughly.

 2016 Marble Institute of America Repairs • Page 21-45

8.3.2 Mix adhesive according to directions color. The resulting compound will cure into supplied by the manufacturer. Add color if an extremely hard material that can be worked desired. in the same way that stone would. It is also capable of taking a polish. 8.3.3 Apply adhesive. Use a razor blade or putty knife to smooth and remove any excess 8.6 Countertop Seam Leveling or adhesive. Most adhesives shrink or settle as Scratch Repair. they cure; as such, it is recommended to leave any excess in the fill areas. 8.6.1 The goal of a multi-piece countertop installation should be scratch-free material and 8.3.4 Allow the adhesive to cure for the time seams that are not easily visible. Sometimes recommended by the manufacturer. there can be unavoidable problems that require addressing from an experienced stone 8.3.5 Grind, hone, and polish the stone as technician. Occasionally, for various reasons, necessary to complete the repair. stone pieces are not perfectly flat. When these pieces are joined together at a seam, especially 8.4 Finishing the Repair. a 90-degree seam, the irregularities are noticeable. There are techniques used by many 8.4.1 In the case of a three-step restoration installers to adjust the material to achieve a procedure (flattening, honing, and polishing), better, more finished look. the de-lippage tools will take care of grinding the glue flush with the surface of the stone. 8.6.2 Seam Setter. The most common technique is to use a seam-setter. A seam setter 8.4.2 If performing a two-step restoration is a device used to draw stone pieces together procedure (honing and polishing), excess filler and fit them at the same plane. should be grinded using a right-angle grinder/polisher with an 80, 120 or 220 grit 8.6.3 Seam Setter + Biscuit. Another, sandpaper. The area should be sanded until the less common, technique is to use a biscuit repair is flush with the rest of the stone. joiner in combination with a seam setter. A biscuit joiner is a device used to cut grooves in 8.5 Tips for a Better Color Match. the concealed edge of joined pieces to give For a better matching repair, it is sometimes them a mechanical anchor to help pieces necessary to mix an inert material with the remain at the same position relative to each adhesive to give it the necessary “body.” The other. In the groove cut by the device an oval- most common inert materials used are marble, shaped biscuit is inserted. For the stone limestone or granite dust. Another possible industry, this biscuit is usually plastic or choice is to mix color-matching unsanded stainless steel. grout with the adhesive. The grout is usually mixed approximately two parts grout to one 8.6.4 Shims. Often after the weight of the part adhesive. Once the compound is countertops is added and the cabinets are thoroughly mixed, check the color match, add loaded, there is structural movement and the curing agent, and proceed to fill the voids settling that changes the original placement of as usual. When grout is mixed with adhesive, these tops. In these case it is best to adjust the it will become darker – as if it were wet. It will tops to their original position by adding hard not go back to a lighter color as it would if it shims. Shims are spacers used to adjust the were mixed with water. The color of the surface position of stone countertops. uncured mix is a good indicator of the cured color. Before adding the curing agent, make 8.6.5 Seam Polishing. When surface sure to lighten the mixture to the desired irregularities are present and countertops

Page 21-46 • Repairs  2016 Marble Institute of America cannot be repositioned to an acceptable as the lippage increases. The idea is to grind the position, then seam polishing can be high side down to the low side: not to grind the attempted. Before proceeding with any work, high and low sides at the same time. Grinding the area must be inspected to determine only the high sections will minimize the whether the seam is within grinding tolerance. physical work needed to flatten the seam, and 1/16” (1.5 mm) lippage is a significant amount it will significantly limit the chances of creating of material to be taken down on a counter. wobbles or dips in the reflection. Because of the height and frequent use of most countertops, it is viewed at and the close 8.6.8 Conclusion. It is always best to proximity to the eyes. Every dip and practice the techniques described within this imperfection is magnified, especially in a well- section in order to develop the skill necessary lit area. The more material that must be taken to achieve acceptable results. For practice, the down, the wider the work area must be to ideal material would be a scrap piece of the ensure a flat surface. A flat surface is free of any same stone from the same lot, but that is not dips or wobbles in the reflection. While a seam always possible. The next best piece to practice of ⅛” (3 mm) lippage can be successfully on would be a scrap piece of the same material removed, flattened, smoothed out and from a different lot or a similar stone. Lighting polished to show no distortion, it is extremely on the job site, in all conditions, needs to be difficult and recommended to only be considered when analyzing the results. Only attempted by the most skilled technician. proceed after practicing and mastering the Lippage of 1/16” (1.5 mm) is the maximum skills described. recommended when grinding a seam in a granite countertop or vertical panel installation. 9.0 RECOMMENDED TOOLS

8.6.6 A seam that has been carefully 9.1 Right-angle Polisher. The prepared and installed with no obvious lippage following features are recommended: should take approximately one to two hours to  3-prong plug for safety complete. Each additional 1/32” (0.8 mm) will  Variable speed dial, up to 3,000 RPM add a significant amount of time to the process.  Locking switch for continuous-on Any additional treatment, such as adding glue operation to the seam, will add additional time. This  Lightweight (6 to 7 pounds, or ±3 kg) process should not be considered a cure for  Variable trigger speed unacceptable seam tolerances. It is more of an upgrade or premium service to provide the  5/8” – 11 TPI spindle thread best possible finished product. As mentioned  10 to 15 amps above, it can also performed to compensate for  Constant speed under load minor lippage instead of removal and replacing a top. 9.2 Turbo-style resin diamond abrasives (designed for use with granite) are the most 8.6.7 High sections of the seam must be preferred abrasive. identified. Because some granite slabs are prone to warpage, the high side may change 9.3 Rigid resin diamond abrasives are positions several times from the front to rear of designed for use on granite floors. the counter. A warped slab or a high/low side that changes from front to back is not indicative of an inferior product, but it is a natural occurrence that sometimes cannot be avoided. Identifying the high side becomes more critical

 2016 Marble Institute of America Repairs • Page 21-47

10.0 RECOMMENDED PROCESS impossible to detect. Client satisfaction is the ultimate goal, so leaving an obvious repair is 10.1 All abrasives should be used with a unacceptable. Educating the client prior to generous amount of water, especially in the repairing the stone will also help the client initial grinding and honing phases of the work. form reasonable expectations of what the During the grinding and honing phase, finished job will look like. abrasives below 1,000 grit are typically used. Granite, and stone sold as granite, is very hard 10.5 Abrasives will often glaze over, and generates large quantities of heat when meaning that the resin in the abrasive will cover grinding, honing and polishing. The abrasives the diamonds, rendering it ineffective. should stay lubricated and cool with the use of Abrasives should be dressed on a regular basis water. to ensure maximum efficiency.1 Refer to the manufacturer’s instructions before dressing 10.2 Water supply can be reduced slightly abrasives. during the polishing phase to improve contact between finer grit abrasives and the smoother stone surface. The polishing phase typically begins with 1,000 grit abrasives, then continues to the finest grit of the series. Water should not be reduced to the point that the area will dry completely.

10.3 Machine control is critical throughout the restoration process, but it is especially important during the grinding and honing stage. Any unnecessary or accidental pressure applied in the wrong area can create more work or even cause irreparable damage to the surface. The abrasives can be worked in a linear motion for part of the procedure, but the majority of the job should be done using tight, clockwise circles. Clockwise rotation is important because this will keep the slurry towards the center of the abrasive. This motion is opposite the motion of a floor machine.

10.4 When refinishing a seam or scratch in granite, the result is often slightly different than the factory finish of the surrounding areas. This is difficult to prevent, but it can be dealt with easily. During the final steps, the work area can be feathered out, or enlarged, while progressing to finer grits. When progressing to the final polishing step, fade the polish out into the surrounding area. This technique will make any difference in gloss or clarity almost

1 Dressing is the process of removing glazed resin, exposing the cutting abrasive. Page 21-48 • Repairs  2016 Marble Institute of America

N/A N/A

Easy

High High High High

Poor Poor

Poor

Good

Good

Likely Good

Ext/Int

Excellent

Moderate

≤ 6≤ month

In AdhesiveIn

Most Costly

Cyanoacrylate

Fast (adjustable)

Not RecommendedNot

Not RecommendedNot

Not RecommendedNot

OK OK

Low Low Low

Best

Easy

Poor

Good

Slight Slight

Ext/Int

Critical

Stronger

Excellent

Excellent Excellent

Forgiving

1 to 2 yrs

Not Likely

Most Costly

More Flexible

Fast (adjustable)

Not RecommendedNot

Urethane (MPPH)

OK OK

High High High

Poor Poor

Good

Good Good

Slight

Ext/Int

Critical

Stronger

Excellent

Forgiving

1 to 2 yrs

Moderate

Somewhat

Most Costly

Acrylic-Epoxy

Fast (adjustable)

Not RecommendedNot

OK

Fair

Fair

High

High High High Poor

Poor

Poor

Likely

Slight

Middle

Stronger

Forgiving Forgiving

1 to 2 yrs

Somewhat

Poly-Epoxy

Vulnerable Vulnerable

In AdhesiveIn

Interior Interior Only

Fast (adjustable)

ADHESIVETYPE

Not RecommendedNot

OK OK

Fair

Low Low Low

Best

High

Good

Likely

Slight Epoxy

Slower

≥ 2≥ yrs

Ext/Int

Critical Critical

Excellent Excellent

Strongest

Moderate

Somewhat

Vulnerable Vulnerable

Most Difficult

Most Common

Stone Fractures

OK OK

Easy

High High High High High

Poor Poor

Poor

Good

Good Good

Acrylic

Ext/Int

Stronger

Excellent

Forgiving Forgiving

Most Costly

6 mo to 1 yr

Fast (adjustable)

Not RecommendedNot

OK

High

High High High

Poor

Poor Poor Poor

Poor

Likely

Slight

Strong

Forgiving Forgiving

Polyester

1 to 2 yrs

Vulnerable Vulnerable

In AdhesiveIn

Least Least Costly

Interior Interior Only

More Difficult

Most Common

Fast (adjustable)

Not RecommendedNot

Not Recommended

Cost

Usage

Clarity

Rodding

Shelf Life Shelf

Doweling

Flexibility

Cure Time

VOC Content Flammability

Bond Strength

UV UV Resistance

Fracture Mode

Shrinkage (after curing) (after Shrinkage

Cosmetic Repair Difficulty

Resistance to "CHALKING"

Penetration (low Penetration viscosity) (low

Resistance to "YELLOWING"

Exterior/Interior Application

Thorough Mixing RequirementMixing Thorough

Resistance to Dampness Cure After

Resistance to Dampness Cure During

Countertop Laminations/Mitered Edges Countertop Laminations/Mitered

Evaporative Ratecomponents) (chemical Evaporative

Component Ratio Accuracy RequirementComponent Accuracy Ratio

Staining Probability (dependent stone)on Probability Staining PROPERTY

 2016 Marble Institute of America Repairs • Page 21-49

NOTES:

Page 21-50 • Repairs  2016 Marble Institute of America

Restoration and 2.0 SURFACE PREPARATION

Maintenance – 2.1 Stripping and Removal of Coatings. When a stone surface has a coating, RESTORATIVE it must be removed before diagnosing what PROCESSES restoration work needs to be done to the stone. Coatings are applied to stone surfaces for 1.0 INTRODUCTION several reasons. If a stone surface has been worn, scratched, or etched, a homeowner or 1.1 The term restoration signifies contractor may apply a coating to “renovating, reconditioning, or returning” inexpensively achieve a shine. Coatings are also something to an “acceptable” or “near original” used to seal stone surfaces. There are two condition. Restoration starts with a distinct categories for coatings: water-based comprehensive inspection of stone type, and solvent-based. Although solvent-based condition of the stone, and possible causes of coatings have been the long-standing product the need for restoration. of choice, there are many hazards associated with their use, including high VOCs and the 1.2 Most often the need for restoration need for respiratory and skin PPE. The arises from the lack of proper maintenance. technology for water-based coatings is Other factors that make restoration necessary improving rapidly, and the industry seems to can include improper cleaning products, wear be moving toward using more water-based patterns, scratches, etch marks, stun marks, products. cracks, chips, breaks, contamination from pollutants such as smoke, leaks and floods, 2.1.1 Coating removal is called “stripping.” contact with wet environments, cold-weather When stripping coatings, it is important to treatments such as salt or ice melt, and work in manageable areas. Failure to do so can degradation from years of normal exposure to cause the coating to cure in areas making it the elements. necessary to repeat the process. A chemical solution is used to emulsify and remove the 1.3 Processes unique to restoration coating from the stone surface. Most acrylic include removing and replacing stained and coatings that are installed on natural stone degraded grout, removing deeper sub-surface surfaces can be stripped using water-based blemishes, marks, soils, scratches, etch marks, stripping methods. Lacquers, urethanes, cracks, chips, stun marks and wear patterns on epoxies, and other clear paints are usually stone, and filling larger holes and cracks with stripped using solvent-based methods. color-blended resins. Restoration involves the use of coarser diamond abrasives, such as 120, 2.1.2 Water-based Coatings. Acrylics 100, 70, and lower grits. Refinishing involves and other waxes are stripped using a stripper the use of finer grit abrasives. Restoration also properly diluted in water as directed by the involves utilizing acidic or alkaline chemicals manufacturer. for more aggressive cleaning and stripping. During any process of restoration or 2.1.2.1 Dwell Time. The stripping solution refinishing, proper safety equipment must be is delivered with either a mop or airless pump used. For example, eye, skin and respiratory sprayer. The solution must be allowed to sit in protection equipment must be used around contact with the coating for a period of time in chemicals, dust, and other hazards associated order to soften and loosen the coating and with the process. cause it to shrink away from the surface of the stone.

 2016 Marble Institute of America Restorative Processes • Page 21-51

2.1.2.2 Agitation and Extraction. After detailing is done by immediate application and the prescribed amount of dwell time, the removal of water-based strippers. surface is scrubbed with an abrasive pad or 2.1.5 Poulticing is a process of stain brush. This removes the remaining coating and removal. A chemical is used to loosen the stain converts it in to a liquid form. When the liquid and an absorbent media is used to draw the becomes thick and colored, it should be stain out of the stone. While this can be used removed from the immediate work area with a on any stone, it should first be determined if squeegee. The immediate work area should be the chemical reaction might have an adverse examined to determine if the desired result has effect of the stone. For example, when an acid been achieved. If more work needs to be done, is used to break down rust in any calcium use the squeegee to move the liquid back in carbonate based stone, the acid will etch the place to continue working the area. If the work stone, making restoration or refinishing is complete, use a wet vacuum to remove the necessary. Poulticing requires the following liquid. This process is repeated until the entire steps. area is complete. 2.1.5.1 Identify the stone type and the type 2.1.3 Solvent-based Coatings. Lacquers and source of the stain. Often this can be and epoxies are stripped using a solvent-based determined by asking the building’s owner, stripper that is petroleum-based or from manager, or maintenance workers. another solvent source, such as soy. Soy-based strippers tend to take longer to process, but the 2.1.5.2 Once the source of the stain has been results are similar to petroleum strippers. identified and removed, refer to Stains & Removal Procedures in the Maintenance 2.1.3.1 Dwell Time. Solvent-based strippers section of this document to take the are gels and are usually applied using a brush or appropriate steps to remove the stain. another type of spreading applicator. The gel is applied in such a way as to leave ¼” of the gel 2.1.5.3 After the appropriate dwell time, on the surface of the coating. Some technicians remove the poultice from the stone. For large prefer to cover the treated surface with plastic areas, a wet vacuum can be used to speed up to keep it wet and allow the stripper adequate the process. time to react. 2.1.5.4 Analyze the results and determine if 2.1.3.2 Agitation and Extraction. After another poultice application is needed. If not, the specified period of dwell time, the surface follow up by cleaning the area with a pH is scraped with a spatula and both the stripper neutral stone cleaner before restoring or and coating are discarded. Follow refinishing the stone. manufacturer’s instructions for rinsing and 2.2 Masking and Protecting. Prior to removal of the gel. stone restoration, adjacent areas should be 2.1.4 Detailing is the process of masked. The term mask is commonly used to completing stripping a coating. It can be done describe the process of applying protecting in several ways, based on the preference of the films or tapes to the surrounding area. The technician and the type of coating being most common items that are masked include removed. One method is to reapply the same carpeting, hardwood floors, thresholds, trim stripper, allowing less contact time, then or moldings, glass, and any and all dissimilar scrubbing and extracting it. This is done using materials or stone types that could be the same methods as described above in the negatively affected from contact with the acrylic removal (water-based coatings). Some cleaner, water, slurry, or polishing compound. technicians use solvents such as mineral spirits, Delicate painter’s tape can be applied directly acetone, or alcohol to break and remove the onto painted surfaces, stained finished wood, remaining residues. Another method of metal, or other sensitive surfaces. Ensure no tape is covering the stone that needs to be Page 21-52 • Restorative Processes  2016 Marble Institute of America refinished. Use caution when taping baseboard speed machine can also be used. Access to extra and finished hardwood because even the most weights is sometimes necessary. delicate painter’s tape may pull paint or stain off of these surfaces. 3.1.3 An edging machine and/or variable 2.2.1 Adjacent areas should also be covered speed angle grinder/polisher is the proper tool with other masking materials, such as static- for edgework close to adjacent, dissimilar floor cling painter’s plastic film. Wax paper and pre- and wall materials. Use the same grit level of taped rolled plastic film is acceptable as well. abrasives and steps that are being used on the Start at the baseboards and apply the masking main section of the floor. material up and along the walls, cabinets, and adjacent flooring surfaces. Spot tape the 3.1.4 A variable speed angle grinder/ masking material to these surfaces to ensure polisher is recommended for wall restoration. that plastic film does not fall into the working 3.1.5 Other Recommended area during the restoration process. Equipment. 2.2.2 Make sure to cut openings in the  A squeegee with a rubber head and plastic film covering vents to allow proper extension pole airflow and to apply the film in a way that does  A wet/dry vacuum not prevent the use of appliances and doors to  Metal bonded diamond abrasives a pantry, closet, or entry. Make certain that (multiple grits) for floor and handheld these accommodations do not allow the machines equipment, abrasives, or water and chemicals  Marble-specific, resin-bonded to cause damage. Use items like caution tape diamond abrasives for floor and and wet floor signs if working in an area where handheld machines (approximately 30 pedestrian traffic is likely. grit through 3000 grit or higher, 2.3 Cleaning. The stone should be depending on abrasive manufacturer) swept, vacuumed, and wet mopped using a pH  Transitioning abrasives to be used neutral stone cleaner prior to restoration. This between metal and resin-bonded will keep grit and dirt from doing further abrasives damage to the stone or causing damage to the  Marble polishing compounds abrasives.  Hog’s hair pads

 Diamond dressing compound or 3.0 MTL REFINISHING AND product to dress diamond abrasives1 POLISHING  pH neutral cleaner 3.1 Preparation. 3.1.6 Surface Preparation. 3.1.1 Equipment. There are many variations of machinery and abrasives. The list 3.1.6.1 Mask and protect the work area as below is an example of what is typically used. described earlier in this section.

3.1.2 For lippage removal, use a heavy 3.1.6.2 Remove baseboards and other trim to ridged planetary machine and/or a swing make the edge work more accessible. machine capable of being weighted. A variable

1 To dress a diamond means to remove metal or resin coating over the abrasive, exposing a better cutting surface.  2016 Marble Institute of America Restorative Processes • Page 21-53

3.1.6.3 Use a vacuum to clean the entire floor, Below are two edging options for lippage making sure there is no debris that could get removal based on job conditions. under the machinery. 3.2.1.1 Option A. If the baseboard and other 3.1.6.4 Remove any coatings or waxes from trim can be removed, the machinery can be run surface using the proper methods described tight to the edge of the wall on the first abrasive earlier in this section. If no coatings are step. The second and subsequent steps will also present, wet mop the entire area with a pH be run tight to the wall. Any scratches along the neutral stone cleaner to remove lingering outer edges will be concealed under the debris. moldings when they are replaced. Put a section of the new molding (baseboard and other trim 3.1.6.5 Repair all cracks and chips. Allow pieces) in place without attaching it to verify patching material to thoroughly cure before that the edges are properly finished. If not, the starting the refinishing process. edges will need to be finished by using handheld equipment. 3.1.6.6 Check for any missing grout at joints and caulk. Fill prior to starting the refinishing 3.2.1.2 Option B. If the baseboard and other process. This will ensure that the color will be trim cannot be removed, then this or a similar a better match when the process is complete. grinding process should be followed. A popular method is to use a 2 X 4-inch piece of wood 3.1.6.7 If the floor was grouted with sanded laid flat along the outer edge of the floor. Use grout, it will need to be removed and replaced this as an edge to complete the first abrasive with unsanded grout. Otherwise the sand in step. On the next abrasive step, flip the wood the grout can become dislodged and can scratch onto the 2-inch side to use as an edge. This the marble during the restoration process. method will help to avoid having heavy scratches against the molding. For the next 3.1.6.8 If the lippage averages more than steps, the edge work will need to be done using 3/32”, it is better to float the floor with the a handheld machine, such as an angle same color unsanded grout to protect the tile grinder/polisher, with the appropriate edges from chipping and/or cracking.2 diamond abrasives. Several steps will need to be done by hand to get a 4 to 5-inch perimeter 3.2 MTL lippage removal is the of the floor complete. The edging process process of grinding the floor flat to help make should match the process that will be it easier to polish and maintain. performed for the entire floor.

3.2.1 Edging. Most floors installed in the 3.3 Steps 1 and 2: First grinding. United States are not laid completely flat, nor Using either option A or B, above, start the are they ground in place, meaning that the floor first grinding step. Place the lowest grit metal has lippage. Before beginning the grinding bond diamonds on the machine. The technician process it is necessary to consider the edges of will need to decide with which metal bonded the floor. In some cases it may be possible to diamond abrasive grit to start the process based stop the grinding process 3 to 6 inches from the on how much material needs to be removed. A edges. This is a method better suited for good baseline choice would be a 70/100-grit experienced technicians. For best results, it is metal abrasive followed by a 120/200-grit better to grind the floor flat to the edges. metal, copper, or electro-plated abrasive. 50- grit metal abrasives are very aggressive and are

2 To float the floor means to fill any low areas with a recommended floating material. Page 21-54 • Restorative Processes  2016 Marble Institute of America mainly used to grind the surface of concrete, optimal outcome, it may be necessary to but are not recommended for use by a progress up to 1800-grit diamond abrasives beginner. Abrasives should be secured to the before moving on to the final polishing process. bottom of the machine by bolts, magnets, or For heavily soiled, worn, or damaged floors, it cup holders. A large quantity of water is may be necessary to start with a 120-grit or necessary for this step, so take precautions not lower abrasive. If the floor is less worn, it may to flood lower floors or have any water escape be acceptable to begin with a 400-grit abrasive. the work area. Build dams or pour stops if Some companies manufacture a 400-grit needed to control water flow to adjacent or abrasive capable of removing etching and lower areas. normal wear. The type of stone being restored also determines the abrasive starting point. For 3.3.1 Initial Grinding should be done in travertine and other stones known to have an out-of-the-way corner. The metal bonded many voids, overworking them with 200-grit diamond abrasive will dig in to the stone upon abrasives or lower can open up the voids and starting the machine. Work 50 to 100 square make it necessary to fill them. foot sections for the first step and run the machine north to south and then east to west. 3.4.1 Picture Framing. If lippage is not The goal is to level the floor in sections and removed, diamond abrasives will not abrade then blend it all together. This step is noisy and the low sections of the tile edge, leaving a time consuming, signaling that the floor is not diamond hone on the high sections but the yet flat. Using a squeegee, check the area being original finish on the low tile edge. This is worked. Rinse the floor and let it dry. Inspect known as picture framing. The prominence of the area closely for inconsistencies in the picture framing is affected by the thickness of abraded finish. It is critical to finish this step the abrasives being used. Diamond abrasives with a uniformly abraded surface. There will are commonly produced in thicknesses of 11, typically be some low corners that will need 9, 4, or 3 mm. The thicker the abrasive, the more attention. If inconsistencies are found, more rigid it tends to be and the more continue to go over those areas until it is pronounced the picture framing would be. If uniform. This step will set the precedent for the technician is not being contracted to the remainder of the processes. remove the lippage by grinding the floor flat, it is better to use 4mm or thinner diamonds with 3.3.2 An equal or greater time should be a foam spacer for additional flexibility to spent on the seconding grinding. Make sure reduce the picture framing affect. that all of the previous grit’s scratches have been removed. If this process is not performed 3.5 Step 3: Light grinding or correctly, it will be noticeable in the final transitioning (step 1 if lippage removal polish of the floor. After the 120/200-grit is is not performed). For refinishing, it is most complete, the floor is ready for the refinishing common to begin with 220-grit diamond phase of the process. abrasives. To begin, the technician attaches the abrasives to a flexible riser pad. The two most 3.4 MTL Refinishing. When refinishing common diamond configurations are 3 or 4 a floor without lippage removal, the technician abrasive pads. If using 3 abrasives, the must determine the abrasive coarse enough to technician should place the diamonds evenly on quickly remove the deepest scratch without the drive plate (for example at 12, 4 and 8 being too aggressive and causing additional o’clock positions), forming a triangle pattern. work. In most cases it is best to begin with 200- If using 4 abrasives, the technician should space grit diamond abrasives, then progress to 400- them evenly on the drive plate (for example at grit and 800-grit prior to final polishing on 12, 3, 6 and 9 o’clock positions), forming a most marble. In some cases, to obtain the square pattern. Spacing of the abrasive from

 2016 Marble Institute of America Restorative Processes • Page 21-55 the outer edge of the drive plate is one method move the machine in circular motions. This is used by experienced technicians to ensure a used across each section covering the same more thorough overlap is achieved with finer area, in the same amount of time, to ensure the grit abrasives. stone is hit from different angles. Once a section is finished, all water and slurry should 3.5.1 If using a machine with a water tank, be moved from the working area using a engage the water flow for 3 to 5 seconds at the squeegee, then extracted with a wet vacuum. beginning of the process to apply enough water Do not let the slurry dry on the surface of the to the working surface. Only enough water is stone. A clean, dry surface is necessary for the needed to create a slurry with the consistency technician to inspect the work at each step to of skim milk. If water is running from the ensure that there are no inconsistencies in the working area onto the low areas on the floor, abrasive pattern before moving to the next too much water was used. Excess water will step. Using a squeegee to assess each area is the not affect the abrasive’s ability to work in the quickest technique. This step is accomplished initial stages, but it will cause potential work more efficiently if a second technician is on site problems such as water flowing into floor hand to operate the squeegee and vacuum. This vents and through ceilings of the lower level allows the first technician to move on to the floor. If necessary, add additional weights to next section of the floor while the second is the machine to increase the cut rate. Be careful vacuuming the previous section. when adding weight to the machine while working on filled stone like travertine. This 3.6 Step 4: Light grinding or initial will make it necessary to fill the voids created honing step (step 2 if lippage removal is by overworking the stone. not performed). After the entire surface has been finished with 220-grit diamond abrasives, 3.5.2 Begin grinding in the far corner of the remove them from the drive plate and attach room, working backwards towards a natural 400-grit abrasives, also using foam spacers. stopping point, such as a front door or room These abrasives should be attached in the same transition. It is helpful to visualize the floor in pattern as before, but placed slightly closer to 10 to 20 square foot sections and work each the outer edge of the drive plate. This allows section moving from right to left or left to right the technician to move the machine along walls in linear movements. When working in lower and cabinets and easily overlap each grit level. grits (200 and 400 grits), it is better to make two passes before moving down through the 3.6.1 This step in the refinishing process can section. By making two passes, the technician be thought of as the matte process of the honing will move the machine in a linear pattern from phase. Each finer grit diamond abrasive will right to left or left to right, then reverse and improve the color, shine, and clarity of the move the machine over the same footprint surface until a polish is produced. returning to the starting point. Approximate coverage rate should be 10 square feet every 5 3.7 Step 5: Honing step (step 3 if minutes when moving in a straight line. The lippage removal is not performed). After technician should ensure 50% overlap of each finishing the entire floor with the 400-grit, the pass throughout the floor. When using one pass surface should be rinsed, vacuumed, and dried. (or 2 passes at lower grit levels),when the area The floor should be inspected to ensure that is completed the technician should step back there is a consistent abrasive pattern and that it only about half of the width of the machine and is ready for the next step. After 400-grit, each reverse directions, moving at the same pace subsequent grit can be thought of as a polishing stated above. This will ensure there are no grit. The 800-grit abrasives should be attached missed areas that will cause problems at the to the drive plate as before, but moved even polishing stage of the project. Some technicians closer to the edge of the plate.

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3.7.1 When refinishing MTL floors, it is Slurry should not be tracked onto other common to stop after finishing with 800-grit. sections of the floor, because it can create etch Some technicians choose to progress to 1800- marks. Think of the floor in sections. On most grit or even 3000-grit. With 800, 1800 and MTL floors it is acceptable to polish 20 to 30 above grit steps, it is acceptable to deviate from square foot sections at time. Place the polishing the process above. The technician can perform compound of choice on the floor by pouring it just one pass in each direction. This means that in a circle approximately 14 inches in diameter. if the technician is moving from right to left, When the machine head is put in contact with when they reach the opposite edge of the the floor, it should cover the applied working area it is acceptable to take a step back compound. This will reduce the spray or half of the width of the machine and reverse spread of the compound across the floor. It is direction. This makes work with the higher common to use ¼ to 1/3 of a cup of compound grits progress much quicker. The hardness and in each section of the floor. Place a white or color of the stone being refinished usually has natural hog’s hair pad to the drive plate, an impact on how fine the last grit needs to be. ensuring that the plate is centered on the pad. With experience, the technician will know Drop the machine head over the powder and how far to take this part of the process. apply water. If using a machine with a water tank, engage the water flow for 3 to 5 seconds 3.8 Step 6: Polishing step (step 4 if at the beginning of this process. lippage removal is not performed). Prior to polishing, make sure masking is still intact. 3.8.3 Once the machine has started, work in Polishing compounds contain acidic circular motions covering approximately a 20- components that could damage metal or other inch diameter section, while moving in a linear adjacent surfaces. This step is typically the pattern. As with the diamond refinishing steps, messiest, so proper masking will reduce clean it is important to overlap the work areas to up time upon project completion. Polishing ensure an even and uniform finish over the compounds are covered in much more detail in entire floor. Most technicians will check the chapter 5 of this document (Equipment). polishing progress with a squeegee. When the desired polish has been achieved, rinse the 3.8.1 After the floor has been refinished working area and extract the slurry from the using traditional abrasives, it is ready for floor. Total working time per section should be polishing. If at this point there are still picture between 90 seconds and 3 minutes, depending frames, low points on the tile that are on floor type and compound used. This step untouched by abrasive and appear polished, should be repeated until the entire floor has they should be minimal and will be completely been covered and the desired results have been removed by an experienced technician during achieved. the polishing step. There are a number of compounds that will achieve the desired result. 3.8.4 After the floor is polished, there will The amount of compound used and time spent be residue in grout lines and on the surface of in each section varies slightly based on the the tile. To remove the residue, add a pH hardness, mineral makeup, and color of the neutral stone cleaner to the water tank of the stone and compound being used. The processes machine or apply the cleaner to the floor using as described below are general guidelines that a pump sprayer. Then place a clean white pad may need adjustment in the field depending on or soft brush on the machine. Starting at the far job site and product variables. end of the floor, working backwards toward a door or room threshold, scrub the floor to 3.8.2 Begin in a far corner of the room, remove residue from the tile and grout lines. working backwards towards a natural stopping While the cleaner is still on the floor, use a point such as a front door or room transition. sponge to clean edges and corners to remove

 2016 Marble Institute of America Restorative Processes • Page 21-57 residue and debris. When the floor is dry, 3.10.4 A Brushed Finish is achieved by remove all tape and plastic film, then using abrasive brushes in place of rigid abrasives thoroughly dust mop the floor. The floor is to hone the surface of the stone. Materials that now ready for sealing. have a wide range in hardness usually produce the most diverse texture using this technique. 3.9 Sealing (using an impregnating Materials that do not contain a wide range of repellant). For sealing, refer to chapter 8 of minerals with varying degrees of hardness are this document (Sealers). In general, a simple often textured mechanically before being water test on the surface of the stone will honed with the abrasive brushes. These brushes determine its porosity. If the stone darkens usually start at 36 grit and continue to 1200 grit when wet, sealing the stone can be beneficial. for an even finer finish. It is always best to The general rule that applies to sealing stone is research and experiment with different finishes to start with a thoroughly clean and dry floor. to avoid damaging the installed floor. Follow the manufacturer’s recommendations for applying their product. A majority of sealer-related problems are caused by not 4.0 GRANITE REFINISHING following directions properly. AND POLISHING

3.10 Other Finishes. Polished is still the 4.1 Process. The scope of this section most popular finish for stone. Other finishes includes all stones traded as granite by the typically seen on MTL are honed, bush- stone industry. Refinishing and polishing a hammered, tumbled, and brushed (also known granite floor is considered a pinnacle as antiqued, leathered or caressed). A floor will achievement for any stone refinisher. A sound sometimes have a mixture of finishes in a plan and the right tools and equipment are pattern, making refinishing difficult. required. The technician must research Understanding the factory process of creating available machinery and abrasives. Chapter 5 these different finishes can be beneficial during (Equipment) is a good place to begin this refinishing. research. The machine and abrasive needs will vary. 3.10.1 Honing. A honed finish is achieved by stopping the process at least one step before 4.1.1 Technicians must be patient when achieving a polish. The typical honed finish is working on granite. To achieve a factory-like defined as being a matte or non-gloss finish finish, some technicians may state that granite without visual abrasive patterns. With MTL, floors can be refinished without grinding by this usually begins at the light grinding and using only resin diamond abrasives and granite honing steps. polishes. This is possible under the right conditions and on the right floor, but there are 3.10.2 Bush-hammering is a mechanical many variables that affect the results. finish produced from impact by hand or a pneumatic hammer that creates a textured 4.1.2 Granite refinishing becomes necessary surface. It is typically used on cubic material; for several reasons. Technicians may be called stone with a thickness greater than 2 inches. to restore a badly worn or abraded surface or a new floor installation with excessive lippage. 3.10.3 A Tumbled Finish is usually Another reason would be to change the achieved by placing smaller pieces of stone tiles existing finish (changing from a polished to in a tumbler, causing a chipped and worn look honed or honed to polished floor) for any on unused pieces of stone. Bush-hammering, number of reasons. It is also possible to be sandblasting and other methods can be used to called in to brush or texture a granite floor. give larger stones a tumbled look. Textured finishes are becoming more popular

Page 21-58 • Restorative Processes  2016 Marble Institute of America each year, so it is important to understand the 4.3.3 Use a vacuum to clean the entire floor, process. making sure there is no debris that could get under the machinery. 4.2 Equipment. There are many variations of machinery and abrasives. The list 4.3.4 Remove any coatings or waxes from below is an example of what is typically used. the surface using the methods described in  A heavy ridged planetary machine section 2.1. and/or swing machine capable of being weighted. A variable speed 4.3.5 If the floor was grouted with sanded machine is preferred. Access to extra grout, it must be replaced with unsanded weights can be necessary. grout.  An edging machine and/or variable speed angle grinder/polisher 4.3.6 If lippage averages more than 3/32”, it is better to float the floor with the same color  A squeegee with a rubber head and unsanded grout to protect the tiles from extension pole chipping and/or cracking.  A wet/dry vacuum  Metal bonded diamond abrasives 4.4 Granite Lippage Removal. Before (multiple grits) for flor and handheld refinishing, all lippage must be eliminated so machines that the floor is flat. This is a once in a lifetime  Granite-specific, resin bonded process for a granite floor that increases its diamond abrasives for floor and value exponentially. handheld machines - approximately 30 grit through 3000 grit or higher 4.4.1 Edging. Edges must be considered (depending on manufacturer) before beginning the grinding process. In some  Copper-bonded diamond abrasives or cases it may be possible to stop the grinding hybrids used for transitioning between process 3 to 6 inches from the edges. This is a metal and resin-bonded abrasives method better suited for experienced  Other transition abrasives for use after technicians. For best results, grind the floor grinding to remove any excess flat to the edges. Below are two edging options scratches and prepare surface for for lippage removal. honing 4.4.1.1 Option A. If baseboards and other  Granite final polishing compounds trim can be removed, machinery can be run  Hog’s hair pads for polishing tight to the edge of the wall on the first abrasive  Diamond dressing compounds or step. The second and subsequent steps will also product to dress diamond abrasives be run tight to the wall. Any scratches along the  pH neutral cleaner outer edges will be concealed under the replaced moldings (baseboards and other trim 4.3 Surface Preparation. pieces). Put a section of the new molding in place without attaching it to verify that the 4.3.1 Mask and protect the work area as edges are properly finished. If not, the edges described in section 2.2. will need to be finished by using handheld equipment. 4.3.2 If possible, remove baseboards and other trim to make edge work easier and more 4.4.1.2 Option B. If baseboards and other accessible. trim cannot be removed, then this or a similar grinding process should be followed. Use a 2 X 4-inch piece of wood laid flat along the outer

 2016 Marble Institute of America Restorative Processes • Page 21-59 edge of the floor. Use this as an edge to uniformly abraded surface. If inconsistencies complete the first abrasive step. On the next are found, continue to go over those areas until abrasive step, flip the wood onto the 2-inch they are uniform. Areas with negative lippage side to use as an edge. This method will help should be worked using handheld machinery to avoid having heavy scratches against the avoid the risk of overgrinding, but be careful molding. For the next steps, the edge work when using handheld machinery not to create a will need to be done using a handheld machine, dip in those areas. It may be a better to add such as an angle grinder, with the appropriate weight to the machine and make the diamond abrasives. Several steps will need to corrections on the second step. be done by hand to get a 4 to 5-inch perimeter of the floor complete. The edging process 4.6 Step 2: Second grinding step. should match the process that will be When the first step is complete and consistent, performed for the entire floor. begin the second grinding step. Attach the next set of grinding abrasives to the machine. The 4.5 Step1: First grinding step. Using machine can be run in any direction that option A or B (above), start the first grinding ensures adequate surface coverage. Work the step. Place the lowest grit metal bond entire floor and remove all scratches from the diamonds on the machine. The metal bonded previous grit. Run the machine as close to the diamond abrasive grit used to start the process edge as possible. After completing this step, should be determined based on how much rinse, dry, and examine the floor. This step material needs to be removed. Although many must be finished with a uniformly abraded variations can be used, a good baseline choice surface. Once the abraded surface is consistent, would be a 46/50 grit followed by a 100 grit move to step 3. If using option B (described in abrasive (depending on the abrasive section 4.4.1.2), complete the edging work manufacturer). using a handheld machine before moving to step 3. 4.5.1 Abrasives must be secured to the bottom of the machine by bolts, magnets or 4.7 Step 3: Transition step. This step cup holders to ensure the first step goes transitions from metal-bond to resin-bond smoothly. This step requires a great deal of diamond abrasives. Use copper, ceramic, water; build dams or pour stops if needed to phenolic, or granite-specific resin-bond control water flow to adjacent or lower areas. diamond abrasives to remove scratches from Start the machine at approximately 300 to 500 the last grinding process. It is usually best to rpm, then find a speed that works best with the drop to a lower grit than the last metal-bond abrasives and the granite. Work 50 to 100 grit used. For example, if the last metal bond square foot sections for the first step and run grinding grit was a 100, step 3 should start with the machine north to south, then east to west. a 50 grit transition abrasive. Remove all Level the floor in sections and then blend scratches from previous grits and finish with a together. It will take approximately 30 to 60 uniform abrasive pattern. If using option A, minutes for 50 to 100 square feet. This step is continue working each grit to the edge of the noisy, indicating that the floor is not yet flat. floor. If using option B, work the grit over the When the machine quiets down and becomes last metal cut to start blending each cut into the smooth, the floor is getting flat. This step sets edge previously created. Clean, dry, and the precedent for the remainder of the process. inspect the entire floor for uniformity before moving to the next step. 4.5.2 Using a squeegee, check the area being worked. Rinse the floor and let it dry. Inspect 4.8 Steps 4 through 10: Honing and the area closely for inconsistencies in the polishing steps. When floor is thoroughly abraded finish. This step must finish with a clean and dry, inspect before proceeding.

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4.8.1 Step 4. Attach 50 grit (or comparable 4.9 Step 11: Final polishing step. The grit) resin-bond diamond abrasives to the final polishing will only be as good as the machine. The machine can be run in any honing of the surface. Simply put, if the floor is direction that ensures adequate coverage of the honed well, the polishing results will reflect surface. Work the entire floor and remove all that work. scratches from the previous step’s grit. After completing this step, rinse, allow the floor to 4.9.1 There are many polishing compounds dry, and inspect. If the abrasive pattern is on the market, and each has its own strengths uniform, move to step 5. and weaknesses. For highly competitive jobs, an inexpensive but effective compound is often 4.8.2 Step 5. Attach 100 grit (or used. Stone that is polished with a chemical comparable grit) resin-bond diamond abrasives compound should receive a final cleaning with to the machine. Continue with the same a pH neutral cleaner. The easiest compounds process as Step 4. to use will be compounds that can be worked wet. Some companies prefer granite 4.8.3 Step 6. Repeat step 4 using 200 grit crystallizers that are applied using #1 grade resin-bond diamond abrasives. steel wool.

4.8.4 Step 7. Repeat step 4 using 400 grit 4.10 Sealing (using an impregnating resin-bond diamond abrasives. repellant). For sealing, refer to chapter 8 of this document (Sealers). In general, a simple 4.8.5 Step 8. Repeat step 4 using 800 grit water test on the surface of the stone will resin-bond diamond abrasives. determine its porosity. If the stone darkens when wet, sealing the stone can be beneficial. 4.8.9 Step 9. Repeat step 4 using 1500 grit The general rule that applies to sealing stone is resin-bond diamond abrasives. to start with a thoroughly clean and dry floor. Follow the manufacturer’s recommendations 4.8.10 Step 10. Repeat step 4 using 3000 grit for applying their product. A majority of resin-bond diamond abrasives. sealer-related problems are caused by not following directions properly. 4.8.11 Considerations. Inspection after Step 7 is typically more critical as you move 4.11 Other Finishes. Different finishes into the honing and polishing phases. This can are increasingly becoming more popular for give you a glimpse of the consistency of the natural stone. Finishes typically seen are final polish. If the surface is uneven, it is honed, flamed, bush-hammered, and brushed imperative to go back over the floor until it is (also known as antiqued, leathered or consistent. The speed of the machine can be caressed). Most granite can be flamed and this increased when using the finer grit abrasives. is a popular choice for improving slip For example, on Step 9 (1500 grit) the speed resistance. On occasion, a floor will have a can be set to 1,100 RPMs. During the use of mixture of finishes in some form of pattern, finer grit abrasives there is less material being making refinishing difficult. Understanding the removed and the water required to keep the factory process of creating these different stone and the abrasives cool is reduced. A finishes can be beneficial when refinishing it. heavy water flow during this phase increases the changes of hydroplaning or reduced stone 4.11.1 A Honed Finish is achieved by to abrasive contact. However, too little water stopping the process at least one step before will cause the abrasive to heat up and glaze achieving a polish. The typical honed finish is over. defined as being a matte or non-gloss finish without visual abrasive patterns. With granite,

 2016 Marble Institute of America Restorative Processes • Page 21-61 this usually begins at Step 7 and continues to Buff pads typically come in black or white Step 9. varieties and contain extremely high grit abrasives (8,000 or 11,000-grit). The use of 4.11.2 A Flamed Finish is achieved by using the buff abrasive pad will result in a high quality and oxygenated torch to heat the surface of the mechanical finish. When polishing granite, the granite to approximately 1,600 degrees better quality mechanical finish the technician Fahrenheit. This process is not recommended can achieve, the easier it is to achieve an for installed stone without thorough research acceptable polish using chemical and abrasive and trials. granite polishing compounds.

4.11.3 A bush-hammered finish is 5.2 Equipment. The following typically used on cubic material. It is a equipment is recommended for granite mechanical finish produced from impact by countertop polishing: hand or a pneumatic hammer that creates a  Variable speed right-angle textured surface. grinder/polisher  3, 4, 5, or 7-inch backer pad 4.11.4 A Brushed Finish is achieved by  3, 4, 5, or 7-inch diamond abrasives using abrasive brushes in place of rigid abrasives to hone the surface of the stone. Materials that  Water supply (spray bottle or water have a wide range in hardness usually produce supply for a center water feed the most diverse texture using this technique. polisher) Materials that do not contain a wide range of  Squeegee minerals with varying degrees of hardness are  Granite polishing compound often textured mechanically before being  Hog’s hair burnishing pad honed with the abrasive brushes. These brushes  pH neutral cleaner usually start at 36 grit and continue to 1200 grit for an even finer finish. It is always best to 5.3 Surface Preparation. Before research and experiment with different finishes beginning the refinishing process, adjacent to avoid damaging the installed floor. areas (including floors, cabinets, walls, mirrors, ranges/cooktops, and refrigerators) should be masked. Delicate painters tape can 5.0 GRANITE COUNTERTOP be applied directly onto painted surfaces, POLISHING finished wood, metal, and other sensitive surfaces. 2” painter’s tape can also be applied 5.1 Granite is naturally resistant to to the edge of the counter, leaving scratches, chemicals (it is not acid sensitive), approximately 1 to 1½-inches of tape above and moisture. Because of this, most granites the surface of the countertop. This will reduce maintain a high quality finish. It is not unusual splatter and necessary cleanup. Use caution for granite countertops to be serviced in 5-7 when taping painted cabinets and finished year windows or longer. In most cases only hardwood because even the most delicate spot refinishing is required to remove a scratch painter’s tape may pull paint or stain off of or other imperfections from a portion of the these surfaces. countertop. These smaller areas can be polished to blend in with the entire 5.3.1 Other masking materials should also countertop. Because they are naturally scratch be used. The most common masking material resistant, granite countertops rarely, if ever, is static-cling painter’s plastic film. Wax paper require refinishing using diamond abrasives. and pre-taped rolled plastic film are also When they do, abrasives up to 3,500-grit acceptable. Starting at the top of the cabinets followed by a buff abrasive pad should be used. just below the countertop, unravel masking Page 21-62 • Restorative Processes  2016 Marble Institute of America material down and along cabinet faces. Then Inspect the area closely to ensure that there is a use a small piece of plastic to cover the range consistent abrasive pattern. Once the or cooktop. Plastic film or canvas tarps should imperfection has been successfully removed be laid on the floor in the working area. and the abrasive pattern is consistent, move to Review the surroundings and cover furniture the next step. or other items that are close enough to be hit by splatter with plastic film or canvas tarps. 5.4.3 Repeat the process above with the Masking for countertop refinishing is designed next finer-grit abrasive. Overlap the previous to catch splatter. The splatter caused by scratch profile by about 25% of the abrasive countertop refinishing and polishing footprint to prevent a halo. Continue by compounds will generally not stain or damage moving the machine in a consistent pattern floors, cabinets, or nearby furniture, but across the designated work area with each protecting these surfaces with plastic film abrasive. The abrasive part of the work is provides a professional look and greatly completed when technician has progressed to reduces clean up upon completion of the the use of the buff pad and achieved a near project. factory shine mechanically. By overlapping and thoroughly inspecting the work, the reflective 5.4 Refinishing. Begin by identifying the finish will be the same from the center to the area that requires refinishing. If it is a small outside of the scratch profile. scratch or small area, use a china marker or lumber crayon to circle the scratch. 5.4.4 When using higher grits (1000-grit and finer) some technicians prefer to use the 5.4.1 Use a variable speed right-angle tool wet-to-dry. To do this, use a sprayer to grinder with a 3, 4, 5, or 7-inch backer pad. It apply a mist of water on to the work area. Start is common to refinish small areas using 3 or 4- the machine on the lowest speed, applying inch diamond abrasives. Spray the working area more pressure than usual to the machine. with water. Allow for consistent and even Work the area back and forth until the area water distribution; do not flood the surface. begins to dry out. As the area dries out, the Choose a coarse grit abrasive (typically 50, abrasive will start to grip the surface and jerk 100, or 200-grit) and attach it to the backer the machine. Apply more pressure to the pad. Use the highest or finest grit abrasive tooling head, creating more friction and heat. capable of effectively removing the The work area will completely dry out. As this imperfection. This will decrease the steps happens, continue applying pressure while necessary to achieve the desired result. increasing machine speed no higher than the middle speed setting of approximately 3,500 5.4.2 After selecting the abrasive, place the RPMs. machine flat on the surface and run the machine in an even, consistent pattern across the 5.4.5 At this point, the work area should working area. The first step is not completed start to show a polish but the color will appear until the imperfection is removed. It may be muted or greyed in comparison to the rest of necessary to pause and spray more water onto the countertop. The depth and clarity of the the surface if a constant water supply is not reflection in the working area will be slightly being used. Ensure that the edge of your diminished when compared to unworked working pattern (also known as the scratch areas. The surface is now ready for the use of profile) is even and does not show arrant polishing compound. scratches. Stop to clean slurry off the working area, using a rag or small squeegee to check 5.4.6 There are several different types of progress. When finished with each step, clean granite polishing compounds. Some are strictly the working area and dry it for inspection. abrasive products that contain aluminum or tin

 2016 Marble Institute of America Restorative Processes • Page 21-63 oxide. Others are creams that combine it is common to polish the entire countertop chemical and abrasive technology. Regardless surface with a granite polishing cream using a of the type of compound used, most hog’s hair burnishing pad or a spray technicians use a hog’s hair burnishing pad that polish/crystallizer with a steel wool pad. The is cut to fit the backer pad (pad driver) to finish hog’s hair pad or steel wool pad is cut to fit the polishing the work area. machine’s backer pad. Both processes remove grimy buildup that dulls a countertop. This 5.4.7 If a traditional powder is used, add process enhances the color and shine of the enough powder to cover the area. Spray with stone and restores the surface to the level of enough water to wet the powder slightly, then finish the customer desires. place the machine on the wet powder. With the dial set to the lowest speed, start the 5.6 Sealing (using an impregnating machine. The process should produce a thick repellant). For sealing, refer to chapter 8 of slurry of polishing compound. As the slurry this document (Sealers). In general, a simple dries onto the surface, spray a small amount of water test on the surface of the stone will water to keep the surface and polishing determine its porosity. If the stone darkens compound wet. As the compound dries, add a when wet, sealing the stone can be beneficial. little more, apply pressure, and increase the The general rule that applies to sealing stone is speed of the machine. The added pressure will to start with a thoroughly clean and dry floor. cause friction and heat that creates a better Follow the manufacturer’s recommendations polish. for applying their product. A majority of sealer-related problems are caused by not 5.4.8 If using a granite polishing cream or following directions properly. paste, place a quarter-sized amount on the surface of the work area for a section approximately 8-inches in diameter. Attach a 5 6.0 CRYSTALLIZATION or 7-inch foam backer pad to the machine and use a hog’s hair burnishing pad cut to fit the 6.1 The term crystallization (also backer pad. Start the machine at the lowest known as vitrification and re- speed to spread the product around on the crystallization) describes the act of polishing surface in small sections. Use moderate MTL and other surfaces containing calcium pressure to work the product into the surface carbonate. Crystallizers usually contain in a linear or figure-8 pattern. As the heat magnesium hexafluorosilicate or a like generated by the machine dries the cream, compound. The compound is designed to react increase the speed of the machine and maintain with the surface of MTL and chemically etch a a light pressure. After a few passes it may be shine into the surface. Although the majority of necessary to increase the speed to the middle crystallizers are liquids, magnesium setting of approximately 3,500 RPMs and hexafluorosilicate is naturally a solid white salt burnish the surface to achieve the high-gloss and is present in many commercial marble deep color of a factory finish. It may take polishing powders and pastes. multiple applications to achieve the desired finish and depth of color. The surface is ready 6.2 The polishing medium used during for sealing when the desired level of polish and crystallization is a hog’s hair pad, a white pad, depth of color are achieved. or a steel wool pad. Steel wool is the most popular polishing medium used to crystallize a 5.5 Cleaning and Polishing. Because MTL surface. However, many newer products granite holds up so well and rarely requires have been introduced that can be successfully refinishing, technicians are often asked to clean used with hog’s hair or white pads. When using and polish granite countertops. In these cases, steel wool, the fragments left behind can rust

Page 21-64 • Restorative Processes  2016 Marble Institute of America causing staining to the stone and grout. Vacuuming or using a magnetic broom should always follow the use of steel wool to ensure that all fragments are removed.

6.3 Popularity. Crystallization is popular is because the average well-trained maintenance professional can crystallize 300 (or more) square feet per hour. A steel wool pad typically lasts 300 to 500 square feet when both sides are used. Crystallization is performed with a janitorial swing machine (also known as a janitorial buffer or floor buffer). A drive plate with sufficient “grab” to turn the steel wool is all that is needed. The operator usually pours the crystallizer, undiluted, into a chemical squirt bottle and sets the nozzle to a medium mist.

6.4 Process. Start from the upper left of a room or area (based on the revolutionary turn of the machine) and work toward the door or exit. Add a small amount of liquid to the surface and move the machine with the polishing media across it. Buff the surface until the streaks and liquid disappear. The movements should be overlapping to make sure all spatter marks are removed. Most technicians will work a five square foot area and work backwards, but some technicians work larger areas. After a short period of time, the steel wool pad will become loaded with residue from the buffing process and removal of excess crystallizer. When this happens, turn the pad over and buff the area just completed to remove final residue. The entire service area will be treated in the same way.

6.5 Dust will settle on the floor after polishing is complete. This is usually from the steel wool used in the process. Clean the area with a vacuum, magnetic broom, or microfiber dust mop to remove all steel wool residue. If the cleanup is not performed in a diligent manner, adding water from mopping and maintenance will react with the steel wool fragments and cause the floor to yellow and rust. This is usually seen on the edges of the tiles, in the grout, and sometimes on the surface of the stone.  2016 Marble Institute of America Restorative Processes • Page 21-65

NOTES:

Page 21-66 • Restorative Processes  2016 Marble Institute of America

Restoration and solvent (“Carriers”) into the interior of the stone. When cured, these compounds provide Maintenance – resistance to stain sources or contaminants that are water or oil-borne. Impregnating SEALERS repellents minimally affect the stone’s color, texture, or finish, and require a minimum level 1.0 INTRODUCTION of maintenance. They are composed mostly of silicone-based chemicals and fluoropolymers, 1.1 Sealing is the process of applying and are ineffective against highly acidic or chemical solutions—known as sealers—to alkaline chemical etching. They require the use stone that, when cured, alter the inherent of pH-neutral cleaners. Most importantly, they absorption qualities, increase the resistance to allow moisture vapor transmission (MVT), staining, and/or alter the stone’s appearance which is the natural process of moisture for aesthetic enhancement. transfer through the stone.

1.2 Sealing natural stone is a science 2.2 Color-enhancing Impregnators involving knowledge from disciplines such as are a sub-category of impregnators that contain geology, construction, chemistry, and a higher concentration of actives or solids that maintenance. The larger question is, “Does darken and enrich certain natural stone colors. stone have to be sealed?” The short answer is, They are more viscous in consistency, moisture “No.” Before dimension stone was cut and sensitive, require greater care during polished and set in a home or office, it was just application, and should be applied when the a rock in the ground. There are millions of stone is as dry as possible. Be sure to consult unsealed stone installations with which humans the manufacturer’s directions for specifics. have interacted for hundreds, if not thousands, Color-enhancing impregnators also allow of years. Why is stone sealing now common? vapor transmission (MVT). They accentuate Modern consumers want to protect stone’s color and contrast, texture, and finish appearance, reduce maintenance costs, and variations in the stone and grout and may preserve the investment that stone surfaces create a light sheen. represent. 2.3 Film-forming sealers (also known 1.3 Because of different performance as “coatings” or “topical coatings”) contain goals, desires, and perceived acceptability for higher concentrations of actives compared to stone use, there are different product offerings impregnating repellents or color-enhancing in the market. The sealer product selection impregnators. The actives are deposited by a needs to be made based on sealer type and carrier onto the stone’s surface, where they other criteria as described within this cure and ultimately create a hardened film. document. There are three basic categories of The film-forming sealer creates a sacrificial sealers commonly used in the stone industry. physical barrier between the stone’s surface, potential contaminants, and the environment. They can consist of acrylic, urethane, and 2.0 TYPES AND epoxy chemical compounds. CHARACTERISTICS OF SEALERS 2.3.1 Important Characteristics of 2.1 Impregnating Repellents (also Film-forming Sealers. Film-forming sealers known as impregnators and penetrating protect the stone’s factory finish and diminish sealers) are chemical compounds known as the effects of pedestrian and vehicle traffic. “Solids” or “Actives” (a contraction for “active They can effect slip-resistance when wet, ingredients”) that are carried by water or a unless combined with grit additives, and can

 2016 Marble Institute of America Sealers • Page 21-67 create various types of finishes, from matte to protection. Consult the manufacturer’s high-gloss. Film-forming sealers can enhance documentation for information. Water-based color, texture, and finish variations in the stone sealers are sensitive to lower temperatures, but and grout. They are subject to abrasion, which less sensitive to higher moisture content in the can breach the integrity of the protection the stone. Consult sealer manufacturer for specific film-forming sealer affords and reflect the wear recommendations. Generally, water-based patterns of foot traffic. In the presence of sealers are better for lower density stones with Moisture Vapor Transmission (MVT) they higher porosity. could turn milky white. Film-forming sealers 2.4.2 Actives. Also known as “solids,” require additional cleaning steps and require actives are the chemicals that penetrate the the surface of the stone be maintained by high- stone and cure a few millimeters below the speed burnishing and/or recoating at regular surface. They reside in the intercrystalline intervals. boundary areas and pores of the stone.

2.4 Sealer Components. Sealers are 2.4.2.1 Silicone-based chemicals are used comprised of two main components: carriers primarily for repelling water or water-borne and actives (also known as “solids”). The contaminants. This quality is commonly primary carriers are water and solvent, and referred to as hydrophobic. The actives for this new carriers are being tested regularly. category include silane, siloxane and silicone.

2.4.2.2 Fluoropolymers are used primarily 2.4.1 Carriers. The carrier component of a for repelling oil or oil-borne contaminants. sealer facilitates the delivery of the active This is trait is commonly referred to as ingredients to the interior of the stone. oleophobic.

2.4.1.1 Solvent-based Carriers usually 2.5 General Characteristics of contains higher amounts of Volatile Organic Sealers. Compounds (VOCs). Most solvent-based sealers have strong, distinctive odors and 2.5.1 Sealing can alter the inherent require the use of Personal Protective absorption qualities of stone, increase Equipment (PPEs) and adequate ventilation resistance to staining, and/or alter the stone’s during application and curing. Solvent-based appearance for aesthetic enhancement. In sealers are sensitive to ambient air and surface certain situations, sealers can be employed to temperatures. The stone should be dry. improve slip resistance. Excessive moisture inhibits a sealers’ curing and may also prevent adequate protection. 2.5.2 There are some conditions in which What constitutes “a dry stone” needs to be sealing stone could be ineffective or dangerous. defined by reading the instructions or Moisture, vapor, UV light, landscape, and contacting the sealer’s manufacturer. chemical exposure are all variants that may Generally, solvent-based sealers are better for render sealing inappropriate. For instance, higher density stones with lower porosity.1 freeze-thaw conditions and standing water can create slip hazards, and have the potential to 2.4.1.2 Water-based Carriers usually have damage material over time. Careful less VOC components, less odor, and less consideration of the activities and the environmental regulations concerning their manufacturer’s recommendations will aid in use. They rarely require PPE, though the the selection and application of a sealer for a method of application may require breathing particular installation.

1 Density is the weight of material expressed as its mass divided by volume; porosity is the ratio of a stone’s pores to its total volume; porosity is the ratio of a stone’s pores to its total volume. Page 21-68 • Sealers  2016 Marble Institute of America

2.5.3 Sealers are maintenance products and chemicals and procedures, adequate drying require periodic reapplication. Even though time, and proper application techniques are some manufacturers warrant their sealers for critical to ensure a successful application. certain time periods, because these sealers dissipate and lose their protective quality as time goes on, resealing is required. 3.0 DETERMINING THE APPROPRIATE SEALER 2.5.4 Sealers do not alter a stone’s molecular structure. In stone restoration work, a class of 3.1 After the decision has been made to products known as consolidators and densifiers use a sealer, it is important to narrow the do reintroduce mineralogical components lost offerings. When determining which sealer is from the weathering process in order to slow best suited for a material, stone care the natural deterioration of the stone. These professionals must take several factors into products are not considered sealers. account. It is best to begin with the identification of the stone’s geological 2.5.5 Depending on the type, sealers do classification and identify the protection make stone surfaces more resistant to water, needed. oil, contaminant and weather. Some sealers repel both types of contaminants. However, 3.2 Geological Classification. Proper they are not weatherproofing and stone identification is important when applying waterproofing agents. They act as a barrier, but sealers. Each stone classification has will break down through prolonged exposure performance parameters. These parameters to contaminants. help establish the suitability of a particular stone for the considered or existing 2.5.7 Sealer performance is not dependent installation. on whether a product is solvent-based or water-based. There are varying degrees of 3.2.1 Hardness is a measure of the quality amongst the water-based and solvent- mineral’s resistance to scratching. based sealer categories. The sealer’s quality is based on purity of the carrier, quality of the 3.2.2 Permeability is the capability of a actives used, and concentration of actives in the porous rock or sediment to permit the flow of product. fluids through its pore spaces.

2.5.8 Sealer performance is dependent on 3.2.3 Chemical Sensitivity is a reaction the type of stone, the demands on it, and the to acid or alkaline. Natural stone is categorized location of the installation. Interior or exterior into three basic geological classifications by location, traffic levels, and climate extremes of their respective formation processes: the installation are contributing factors to sedimentary, metamorphic and igneous. product performance and will help determine Additionally, stones in each category can be the sealer selected. Tests should be conducted either calcareous or siliceous, based on their to ensure the right sealer is matched mineral components. These mineral appropriately to a particular stone and components determine the reactiveness of the application. stone to acid or alkaline solutions.

2.5.9 Sealer performance is only as good as 3.2.3.1 Calcareous Stone is composed the technician applying it. Following the mainly of calcium carbonate, a chemical manufacturer’s directions is the best way to compound commonly found in natural stone, ensure a successful result. Thorough cleaning shells, and pearls. Calcium carbonate is and preparation of a stone with approved

 2016 Marble Institute of America Sealers • Page 21-69 sensitive to acidic solutions, so mild, non- Understanding the various types of acidic cleaners are recommended. contaminants and the environmental impact on 3.2.3.2 Siliceous Stone is composed stone applications will provide the information primarily of silicates such as quartz, feldspar, to decide the appropriate sealer. The product and mica. As such, siliceous stone is generally performance expectations must be realistic. It resistant to most acids found in kitchen is important to note that neither impregnating settings. Acidic cleaners are still not repellents nor film-forming sealers can prevent recommended, because these stones may normal weathering and deterioration from contain trace levels of minerals that are normal traffic and use. vulnerable to acid attack, or the cleaners may contain levels of one of the few acid types that 3.4.1 Residential and Commercial attack silicates such as hydrofluoric acid (e.g., Interiors. Always identify the possible toilet bowl cleaners, rust removers, chrome sources for stains, evaluate the materials, wheel cleaners, plant food and wood stones, and sealers relative to the activities and treatments containing ammonium bifluoride). stain sources present, and determine suitability of masking adjacent surfaces prior to sealing. Geological Classification Chart Sedimentary Metamorphic Igneous 3.4.1.1 Considerations for Residential Limestone Interiors. The type of stone and susceptibility Marble Calcareous Travertine Serpentine to reaction, abrasions, and other breakdown Onyx should always be considered, especially when Slate working with polished marble and granite or Siliceous Sandstone Quartzite Granite honed travertine and limestone. The use area Soapstone should also be considered, especially in high-

traffic areas such as kitchens, family rooms, and 3.3 Appropriate Material for the bathrooms/showers. Other factors to consider Intended Use. An analysis of whether the in residential applications include: family size, stone is suitable for the proposed use or pets, and associated use; foods and liquids existing installation is important. First, the (lemon, vinegar, wine, juices, and oils); environment needs to be identified. This is cleaning chemicals (toilet bowl cleaners and often done by consulting plan specifications citrus cleaners); and personal toiletries (lotion, and post-construction manuals and talking to shampoo, conditioner, hand soap). sources such as the homeowner or tenant, building or maintenance manager. Once the 3.4.1.2 Considerations for Commercial nature of the use or environment is and Industrial Interiors. Factors to determined, stone professionals can help consider in commercial and industrial interiors specify materials best suited for that use or include: issues caused by luggage, bell carts, environment. Possible sources to determine dollies, and other equipment; water features suitability can be the stone supplier, a stone and fountains; interior landscaping; proximity maintenance and restoration contractor, an to food courts, restaurants, and common areas; installation contractor, a stone geology maintenance practices and needs; slip resource, or MIA. resistance and safety; increased volume and

traffic patterns; and sealer odors multiplying 3.4 Determining the Potential through HVAC systems. Source of Staining or Problems.

Residential homes require some different care 3.4.2 Exteriors and considerations than commercial or industrial buildings. Because of the different 3.4.2.1 Considerations for Exterior elements of exposure, interior stone behaves Applications. Vapor transmission must be differently from exterior stone. Page 21-70 • Sealers  2016 Marble Institute of America achieved in exterior applications. A lack of 3.5.1 Performance Expectations. There vapor transmission can lead to spalling and can be a trade-off between appearance and other issues. Several other things must be taken functionality. For instance, a film-forming into consideration for exterior applications, sealer provides protection against chemical including: biological growth (moss, algae, exposure to the stone, but usually gives the lichen, and mold), environmental conditions surface a plastic-like look. Each installation is (freeze-thaw, salt water, high water tables, unique and the sealer selection will require acid rain, pollution, UV exposure, and cold consideration of a number of variables, as listed weather treatments such as grit or salt), vehicle in the next section. stain sources (oils, antifreeze, and rubber marks), pitch of surface (should be 2%), 3.5.2 Factors to Consider. Impregnating landscape, fertilizer run-off, irrigation, and repellents are best for maintaining a stone’s water run-off systems. natural appearance. Color-enhancing impregnators best enrich a stone’s color and 3.4.2.2 Further Considerations for character. Film-forming sealers are best for Exterior Applications. Exterior creating low-gloss, semi-glass, and high-gloss installations are unique, because they will finishes. interact with climate and environmental forces as well as human activities. It is important to 3.6 Determining the Desired Level consult with manufacturers to determine their of Maintenance. Maintenance costs are sealer’s suitability with the stone and often overlooked in the process of selecting a installation. A sealer’s resistance to ultraviolet stone and sealers. Maintenance is the most light degradation impacts its effective lifespan. important factor in preserving the appearance In order to prevent freeze/thaw issues, a sealer and protection of a sealed stone. The client’s used in an exterior installation should have an expectations need to be clarified in order to acceptable percentage of Moisture Vapor best assess the material and sealer for the desire transmission (MVT). outcome. Use and traffic, compounded with sealer choice and material used, can all affect 3.5 Determining the Desired maintenance needs. Finished Appearance. The choice of the final appearance of the stone is driven by 3.6.1 Residential Clients typically expect aesthetic considerations, which will be a high level of presentation, but may fail to determined by an architect, interior designer, consider preservation requirements. It is and/or the owner of the property. Aesthetics important to set achievable expectations. Many is a major determinant in sealer selection. As residential clients want a material that usually mentioned above, different sealer types requires a high level of maintenance to be provide unique options for appearance. maintenance free. Residential environments Impregnating repellents provide resistance to are typically maintained on a sporadic basis, staining while retaining the natural appearance depending on the commitment of the owner to and beauty of stone. Color-enhancing the cleaning process. impregnators can darken or bring back the color of polished stone to stone that has been 3.6.2 Commercial Clients, Such as textured or honed. Film-forming sealers Hotel Facilities Managers, are often provide a mechanical or physical barrier concerned about cost, durability, and safety. between the stone and potential stain sources. There are times when these clients have similar Film-forming sealers will also alter the natural desires to the residential client, but there is appearance of a stone, changing sheen of the usually very little emotion tied to their surface from a matte finish to a reflective finish objectives. Commercial environments are or from a reflective finish to a matte finish. typically maintained on a daily basis by either

 2016 Marble Institute of America Sealers • Page 21-71 in-house personnel or contracted cleaning 4.0 BUDGETARY CONCERNS firms. 4.1 Points to Consider. End users need 3.6.3 Guidance in Sealer Selection. to be informed about the projected Type of sealer used and installation location maintenance costs. Facility managers need will dictate the level of maintenance needed. information regarding regular scheduled visits Maintenance refers to regular periodic cleaning and the associated costs. Commercial and with the appropriate products and procedures. industrial applications need regular The installation type determines the cycle of professional maintenance; and require daily or cleaning. nightly cleaning as an ongoing service. Maintenance charts, lists of acceptable 3.6.4 Maintenance Needs. Maintenance products and equipment, training material and charts, lists of acceptable products and training sessions with cleaning companies. equipment, training material, and training Follow up visits by a stone care professional to sessions with cleaning personnel are important ensure that the proper maintenance program in developing a realistic plan to sustain the has by followed. service life of the sealed surface. Sometimes the cleaners recommended for use on stone with an impregnating repellent will contain 5.0 FIELD TESTS FOR small amounts of the sealer. This will help DETERMINING SEALING NEEDS increase or eliminate the interval for reapplication. Check the specific product 5.1 Performing field tests is a common manufacturer’s guidelines as to the industry practice for stone professionals. Most maintenance of their products. A thorough consider water absorption as being an understanding of an end user’s expectations important test, especially if the surface is involves balancing form and function when exposed to water and water-borne applying sealers and because each installation is contaminants. Water beading on the surface is unique, sealer selection involves the not indicative of a sealed stone. The beading of consideration of multiple variables. water demonstrates the properties of surface Impregnating repellents provide longer-term tension. For example, water will react protection and are less costly, due to their less- similarly when applied to factory resin-coated frequent maintenance needs. Also, there needs or enhanced stones and denser stones with to be periodic reevaluation of methods based tighter mineralogical matrices. It is important on product and technique advancements. to note that some natural stones may not require sealing, and can even be negatively 3.6.5 Determining the Tolerance for impacted if sealed. This negative impact is the Volatile Organic Compounds (VOCs). result of the product not being absorbed in to Most solvent-based sealers have strong, the stone and drying on the surface. This is a distinctive odors and require the use of correctable error, but it requires reactivating Personal Protective Equipment (PPE) and the product with a solvent and removing the adequate ventilation during application and residue while the product is in the reactivated curing. If adequate ventilation is impossible state. during the application and curing process, then VOCs must be considered when deciding the 5.2 Selecting the Test Specimen. It is appropriate sealer. Even when there is better to test a sample of the exact material adequate ventilation, the use of personal (same stone and lot) than to risk damage to the protective equipment is still recommended. installed material. The main negative issue with sample testing is the lack of the exact same history of the installed material after use. Sometimes inconspicuous areas, such as Page 21-72 • Sealers  2016 Marble Institute of America closets, also lack chemical treatments that may amount of time left on the surface. Add any have been applied to the conspicuous areas. If other important information such as moisture the issue can be duplicated on a sample or an levels and temperature. inconspicuous area, then proceed by testing the sample or the inconspicuous area. To be sure 5.7.2 Label Test Area. Use a permanent that each sealer is given a fair chance it is marker on the label. Make sure that the marker recommended to determine that each sample or any label adhesive does not stain the stone. or area has similar mineral and porosity Include things that identify the whole area and characteristics. To keep chemical wicking quadrants (measurement marks can also be from affecting your tests, be sure to physically used with axis labels). separate or allow enough distance between test areas. 5.7.3 Exposure. Determine the length of exposure to each contaminant. If it is likely that 5.3 Recommended contaminates for the area may not be cleaned for a week, then basic field testing include: oils (corn, olive, the exposure time needs to be a week or more. coconut, or others that may come in contact On countertops, where they are likely cleaned with the stone), water (or water-based multiple times throughout their use, an contaminants such as tea or coffee), acids exposure of 8 to 24 hours should be sufficient. (vinegar, citrus, fruit juice, etc.), red wine, or any other contaminant that may come in 5.7.4 Execute the Field Test in the contact with the stone. Following Manner. Ensure surface is clean and dry. Apply an adequate, measured amount 5.4 Preparation of the Stone. Clean of the contaminant to the surface (for example: the stone with a neutral pH stone cleaner and 1/2 teaspoon of water, oil, or vinegar). Allow allow to dry for 24 hours or until thoroughly the contaminant to dwell on the horizontal dry. Be sure to follow the preparation surface for five minutes or longer (as procedures recommended by the manufacturer mentioned above). Ideally the contaminant of the sealer. (with the exception of acid) will be repelled for no less than ten minutes when placed on a 5.5 Application of Sealers. Sealers properly cured sealer. Remove the should be applied according to manufacturer’s contaminant by blotting the area. Do not wipe instructions. To get proper protection more to dry. Carefully exam the test area directly than one application may be necessary. afterwards and again later.

5.6 Cure Time. Allow appropriate cure 5.7.5 Results. After the predetermined time per the manufacturer’s exposure time has been reached, clean recommendations. specimens with a neutral pH stone cleaner. Allow the area to dry once contaminant is 5.7 Test Procedures. Stone care removed (approximately 20 minutes for initial professionals must understand how to properly review and sometimes after a day or more perform informal field tests. Testing is the best depending on the results). Visually evaluate way to learn how the specific product or and log results. A successful stone/ sealer test products will perform in a real life setting. would show no absorption, no staining, and no etching. If the stone turns darker, it will stain 5.7.1 Record Keeping. Prepare a written if not sealed. If the stone turns dull and whitish and photographic log to document the test in color, then the stone is likely to etch. methods and results. Note date, time intervals, Another possibility is that an acidic solution can test area, and quadrant. Identify each disturb the impregnating repellent that has contaminant tested, the quantity, and the been applied to a very dense stone so it appears

 2016 Marble Institute of America Sealers • Page 21-73 whitish. In this last scenario, the difference is provides counsel and evidence regarding which that it still has polished reflection. sealers would best preserve a stone’s condition and presentation, and meets the end user’s 5.7.6 Etch Test. When working with an needs. unidentifiable stone, the etch test will confirm if the stone is calcium carbonate based. To 6.2 Important Points to Remember. perform the etch test the stone care Sealers are water, oil, dirt, contaminant, stain, professional should use an acid that is and weather resistant agents only. Sealers commonly used around the stone on different minimize the effects of harmful contaminants, areas of the stone. Serpentines will typically making end-user care and professional only react to mild acids in the calcium maintenance easier and less costly. Sealers are carbonate-based veins. It is recommended to most effective when paired with the test a sample of the same material and lot if appropriate stone and substrate. Sealers possible. If the stone reacts to the acid, it will applied to stone used in exterior and wet need to be restored to the original finish. environments can alter the dynamic coefficient of friction. Appropriate tests should be 5.7.7 Other Things to Consider. Only performed to determine suitability prior to perform these tests in an inconspicuous area or application. Sealers can minimize and slow the on an uninstalled sample tile. It is important to effects of biological, chemical, and physical note that impregnating repellents will not interior and exterior weathering and their repel acidic liquids like vinegar, lemon juice, byproducts, such as exfoliation, fracturing, red wines, tile cleaners, and so on. In fact, frost or salt-wedging, movement, oxidation, acids will damage the surface. Be prepared to slaking, sugaring, etc., but cannot prevent repolish the surface after testing with acidic them from occurring. No natural stone liquids. Topical sealers are much more installation is maintenance-free. effective at repelling acidic liquids.

6.0 FINAL THOUGHTS ABOUT SEALERS

6.1 The stone care professional plays a critical role in determining the selection of sealers. The desired appearance, functionality and maintenance required are all important considerations in the selection process. Whether involved with new construction or maintaining an existing structure, it is important to consult with others involved in the natural stone industry, understand the role of the specifying authority, and the various aspects of stone behavior in relation to environmental suitability to ensure the information provided is thorough, accurate and beneficial. The consummate professional is educated and experienced and has a thorough working knowledge of natural stone, sealers products, and the effects of various environments. The stone care professional

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Restoration and 3.1 Polished-finish Stone has a glossy surface that provides clear reflections and Maintenance – accentuates the color, contrast, and character of the material. Due to abrasion from foot MAINTENANCE traffic, soft stones with a polished finish will generally wear to a dull surface. Due to varying 1.0 INTRODUCTION hardness of the minerals that comprise the stone’s fabric, uniform gloss and/or 1.1 This section will provide end users reflectivity may not always be achieved in all with basic information pertaining to natural stones. stone maintenance. Since general specifications and finishes of natural stone affect cleaning 3.2 Honed-finish Stone has a smooth, procedures, this section will include an overall matte surface with limited reflection. This description of the most common stone finish is generally preferred for softer stone specifications and finishes. It is important to varieties used for floors, treads, thresholds, also acquire background data on the individual and other pedestrian locations where heavy stone(s), such as type and source of stone, type traffic would dull a polished finish. Its lack of of sealer used (if any), and recommendations of gloss makes it a more forgiving surface in that sealer manufacturers as to care of sealed stone, unevenness or waviness will not be as easily etc. detected. Due to varying hardness of the minerals that comprise the stone’s fabric, 2.0 SLIP RESISTANCE OF uniform gloss and/or reflectivity may not STONE FLOOR SURFACES always be achieved in all stones.

2.1 In commercial environments it is 3.3 Maintenance. Regular cleaning important to maintain a log detailing daily and should be scheduled, using specific procedures, periodic maintenance. This log should products, and equipment. Inspections should document the procedures followed on days of be performed at prescribed intervals. inclement weather, such as rain or snow. 3.4 Restoration involves the refinishing 2.2 The Americans with Disabilities of existing stonework to return its appearance Act (ADA). This federal legislation, passed in to that of a newly supplied, unworn product. 1990, is the most comprehensive civil rights This process may include minor repairs such as legislation adopted to prohibit discrimination filling of chips or pits in the stone surface, against people with disabilities. Public and replacement of cracked or missing grout, private businesses, state and local government removal of stains and/or etching, and honing agencies, and private entities offering public or polishing. accommodations and services, transportation, and utilities are required to comply with the 3.5 Purpose and Benefits of law. At one time, ADA documents prescribed Maintenance. a recommended minimum coefficient of friction for walkway surfaces in accessible 3.5.1 Appearance. Efficient regular routes of commercial and public buildings, but cleaning removes fine particulates, which can the section of the ADA documents that abrade and dull the surface of the stone over contained this recommendation have since time. been withdrawn.

3.0 DEFINITIONS, PURPOSE, 3.5.2 Sustainability. Proper maintenance AND BENEFITS OF STONE will lengthen the stone’s service life, effectively delaying the need for more MAINTENANCE  2016 Marble Institute of America Maintenance • Page 21-75 aggressive restoration methods or water used and the dwell time water is allowed replacement. on the stone surface.

3.5.3 Safety. A properly maintained stone 4.2.2 Adhesives. Some adhesives may be surface that is free of contaminants will provide adversely affected by some cleaning agents. a safer walking surface with better, and more uniform traction available for occupant 4.2.3 Grout. Various products are used for ambulation. grouting joints (e.g.: cement, cement with additives, and epoxy), all of which have unique 4.0 CONDITIONS INFLUENC- maintenance and sealing requirements. ING MAINTENANCE 4.2.4 Joint Sealant. Different elastomeric 4.1 Stone type will determine necessary materials are used to caulk joints in finished methods and frequency of maintenance. stonework (e.g.: silicone, urethane, acrylic), Knowledge of the stone’s properties will aid in each of which have unique performance traits designing a maintenance program. For and maintenance requirements. example, granite is a very hard stone with little absorption capacity, while limestone has a 4.3 Characteristics of Certain softer composition and a greater absorption Stones. Many stones have unique features, capacity. The stone properties will also such as fillers, voids, or repairs, which influence the selection of appropriate sealing influence maintenance practices. products. For maintenance purposes, specific groups of stones should be considered in order 4.4 Condition of Stone Installation. to properly maintain them. Residual issues from the initial installation or previous restoration attempts, such as lippage, 4.1.1 Group 1. Stones that typically do not scratches, etch marks, acid burn marks, and contain calcium carbonate and typically do not cracks will influence maintenance needs or react to most common acids: create a requirement for subsequent  Igneous rocks: granite, basalt restoration activity.

 Metamorphic: slate, gneiss, schist 4.5 Location of Installation.  Volcanic: Adoquin, Canterra 4.5.1 Interior. Whether residential or 4.1.2 Group 2. Stones that contain calcium commercial, interior surfaces require careful carbonate and typically react to common, mild consideration of the surrounding materials. acids: Maintenance can impact adjacent surfaces such  Calcite: marble, travertine, as floor molding, furniture, other stone limestone, onyx, terrazzo surfaces, wall coverings, and painted walls. Care must be taken to protect these surfaces or 4.2 Installation Methods and use materials that will not impact their Related Components. appearance or function.

4.2.1 Substrate. The rigidity and quality of 4.5.2 Exterior installations require the the substrate may affect not only the same attention to adjacent surfaces as interior performance of the stone, but also the settings. Additional attention must be paid to necessary maintenance. Some substrates are landscape, vegetation (plants, bushes and very vulnerable to water infiltration, so trees), and water runoff. Check federal, state, maintenance methods must limit the amount of and local codes for building, safety, and environmental requirements.

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4.5.3 High Rise Claddings. Cladding debris, dirt and fine particulate matter. restoration is a specialty area due to the Vacuuming is the preferred method because it difficulty of access and potential influence to lifts abrasive materials up and away from the building seals and curtainwall performance. floor. Dust mops should be dry and untreated. Adjacent materials, such as joint sealers and aluminum and glass curtainwall wall 5.3 Weekly maintenance involves components must be protected from damage washing with clean, potable water and pH by chemical or abrasive cleaning methods used neutral cleaners. Soapless cleaners are on the stone panels. preferred because they minimize streaks and film. Mild, phosphate-free, biodegradable 5.0 MAINTENACE METHODS liquid dishwashing soaps or powders or stone FOR RESIDENTIAL CLEANING soaps are acceptable if rinsing is thorough.

5.1 Products and Equipment. 5.3.1 Process. Wet the stone surfaces with clean water. Using the cleaner (following 5.1.1 Products. Use only stone cleaners or manufacturer’s directions), wash in small, pH neutral cleaners. Some stone cleaners also overlapping sweeps. When using the brush contain small amounts of sealer. These apply light pressure so that only the ends of the products help to maintain the level of bristles are doing the scrubbing. Work from protection. the bottom up if it is a vertical surface. Rinse thoroughly with clean, potable water to 5.1.2 Equipment. New equipment is being remove all traces of soap or cleaner solution. developed continually to clean stone surfaces. Change the water in the rinse pail frequently. Common equipment used includes: Dry with a soft cloth and allow to thoroughly  A small canister vacuum with non- air dry. Alternatively, employ the use of a wet metallic wheels and a flat floor head vacuum to extract contaminants. In with soft bristles made of nylon or commercial applications with high traffic horsehair, or a smooth felt liner along levels, the use of an automatic scrubber fitted the bottom edges. Metal attachments with a disc-type brush system and continuous should never be used. extraction is generally the most effective method. Brush aggressiveness must be matched  Clean cotton string or sponge mop. to the stone type and hardness to prevent Dirty mop heads are a major source of damage. residual soil on the floor.

 Plastic buckets. Never slide the bucket 5.4 Safety Precautions. Any flooring on the floor. If the bucket has wheels, surface, regardless of its finish, can be slippery they should be non-metallic and non- when wet. Promptly remove liquids or foreign marring. materials that might result in safety hazards  In-home steamers. Steamer head rags before permitting pedestrian traffic. Use should be changed frequently. warning cones or other means of alerting  Small scrub brush and/or a deck occupants to a temporary reduction in traction. brush. Bristles should be soft nylon to reduce scratching. 5.5 Precautions. For counter or table tops, use coasters under all glasses, particularly 5.2 Daily Maintenance. The removal those containing alcohol or citrus juices. Many of dirt, debris, and dust is essential to common foods, drinks, and cosmetics contain maintaining the appearance of the floor. All acids that will etch or dull stone surfaces. Use stone flooring should be dust mopped or trivets or mats under hot dishes and placemats vacuumed daily or as necessary to remove under china, ceramics, silver, or other objects

 2016 Marble Institute of America Maintenance • Page 21-77 that can scratch the surface. Blot spills with a 6.1.2 Metamorphic Rocks (slate, paper towel or cloth as they occur or as soon as gneiss, and schist). possible thereafter. Clean regularly with a  Clean daily, using methods outlined in neutral cleaner that does not contain solvents. section 5.0.  Yearly (for floors and stairs): Scrub 5.5.1 In food preparation areas, stone floors with a standard 175 RPM surfaces may require an impregnator or topical buffer, using a soft nylon brush and a sealer. If an impregnator or topical sealer is applied, it must be nontoxic and safe for use on neutral cleaner. An automatic food preparation surfaces. scrubber machine can be used for larger floors. For stairs, use a slow 5.5.2 Never use acidic or ammoniated speed hand polisher. cleaner or chemicals on calcium carbonate-  The stone and/or grout may need based stone surfaces. Use a cleaner specifically resealed at intervals of 2 to 5 years. See formulated for stone cleaning. section 9.0 for more information on sealing. 5.6 Heavy Duty Cleaning. High traffic areas such as kitchens may require a yearly deep cleaning and resealing. This requires the use of 6.1.3 Volcanic Rocks (adoquin and floor machines, brushes, and specialized pads. canterra).  Clean daily, using methods outlined in 6.0 MAINTENANCE METHODS section 5.0. FOR COMMERCIAL CLEANING  Yearly (for floors and stairs): Scrub AND SEALING floors with a standard 175 RPM buffer, using a soft nylon brush and a 6.1 Group 1 includes stones that typically neutral cleaner. An automatic do not contain calcium carbonate and typically scrubber machine can be used for do not react to most common acids. larger floors. For stairs, use a slow

speed hand polisher. 6.1.1 Igneous Rocks (granite and basalt).  The stone and/or grout may need  Clean daily, using methods outlined in resealed at intervals of 2 to 5 years. See section 5.0. section 9.0 for more information on  Yearly (for floors and stairs): Scrub sealing. floors with a standard 175 RPM 6.2 Group 2 includes stones that typically buffer, using a soft nylon brush and a contain calcium carbonate and react to acids. neutral cleaner. An automatic These calcite stones include marble, scrubber machine can be used for travertine, limestone, onyx, and terrazzo. larger floors. For stairs, use a slow  Clean daily, using methods outlined in speed hand polisher. section 5.0.  Stone and/or grout may need to be  Twice yearly: Scrub floors with a resealed at intervals of 3 to 5 years. See standard 175 RPM buffer, using a soft section 9.0 for more information on nylon brush and a neutral cleaner. An sealing. automatic scrubber machine can be  Extremely worn or damaged surfaces used for larger floors. For stairs, use a will require restoration rather than slow speed hand polisher. standard cleaning.  Stone and/or grout may need to be

resealed at intervals of 2 to 3 years See Page 21-78 • Maintenance  2016 Marble Institute of America

section 9.0 for more information on maintenance should include periodic sealing. inspection of stone surfaces for structural  Extremely worn or damaged surfaces defects, movement, deterioration, or staining. will require restoration rather than Distress in joint fillers is a common sign of standard cleaning. stone unit or substrate movements.

6.2.1 Maintaining Finishes on Calcite 7.2.1 The large expanses of stone generally Stones. found on exterior applications may make it impractical to perform frequent normal 6.2.1.1 Polished Surfaces. Buff the stone maintenance. Large installations, however, with a slurry of water and a non-acid polishing should be given periodic overall cleaning to compound. Specialized diamond impregnated remove accumulated pollutants. If the exterior pads can also be used, using a standard 175 stone surface has calcium deposits, an acid RPM buffer or a high-speed burnisher. cleaner can be used on igneous rocks only. Combining the compound with a diamond Easily accessible stone surfaces such as steps, impregnated pad may produce a higher-gloss walkways, and fountains should be kept free of finish. A slow speed hand polisher can be used debris and soiling by periodically sweeping and for stairs, walls, and tops. This should be done washing with water. four times a year, or as needed. 7.3 Local Regulations. Many local 6.2.1.2 Honed Surfaces. Buff the stone with municipalities have regulations related to water a slurry of water and a non-acid honing use and chemical disposal. Always check these compound. Specialized diamond impregnated regulations and authorizations before bidding pads can also be used, using a standard 175 on such cleaning projects; in some cases, there RPM buffer or a high-speed burnisher. are additional costs associated with these Combining the compound with the diamond regulations. impregnated pad may produce a better honed finish. A slow speed hand polisher can be used 8.0 EXTERIOR BUILDING for stairs, walls, and tops. This should be done STONE CLEANING four times a year, or as needed. 8.1 Exterior building stone is 7.0 MAINTENANCE METHODS considered in this section to be all stone used FOR EXTERIOR STONE on the exterior of a structure, either as a structural component or as a facing material, 7.1 Exterior stone is a general term with the exception of polished, finished denoting stone installed where temperature, marble. Although a polished finish is not moisture, and airborne contaminants are recommended for exterior use with most caused primarily or solely by forces of nature. marble varieties, it is occasionally used on It can be used in a honed, textured, or polished storefronts, column facings, and similar finish in any mode in an exterior environment. treatments. Uses include building cladding, walkways, steps or stairs, retaining walls, paving, 8.2 Regular Cleaning. The ideal in fountains, benches, planters, and decorative maintaining exterior building stone is to clean items such as sculptures. it at periodic intervals (at least annually, depending on atmospheric conditions) by 7.2 Normal Maintenance. In accessible simply hosing down with clean water. This will areas, routinely follow maintenance prevent accumulation of dirt and impurities. In procedures as specified in Sections 5.0 and 6.0 accessible areas, routinely follow maintenance of this chapter, as applicable. Normal procedures as specified in Sections 5.0 and 6.0

 2016 Marble Institute of America Maintenance • Page 21-79 of this chapter, as applicable. Brushes may be also oleophobic (oil-repelling). They penetrate necessary for the removal of certain surface below the surface and become repellents. They impurities. Soft fiber brushes are keep contaminants out, but do not stop interior recommended. moisture from escaping. Impregnators are considered breathable, meaning they have 8.3 Sporadic Cleaning. If the stone is vapor transmissibility. not cleaned regularly, a water system (hydraulic, hydro-air, or plain water) will be 9.3 Treatment Type. The type of stone the most effective method at the lowest cost. and environment of the application determine the type of sealer treatment (impregnator or 8.4 Dirt on Older Buildings. When topical) to be used. All treatments must be dirt has accumulated on older structures over a applied in accordance with the manufacturer’s long period of time, a combination of methods specifications. may be necessary to properly clean the stone. A plain water jet will remove most 9.4 When to Seal. A treatment may be accumulation. No chemicals should be used used when a defined benefit can be that could be harmful to the stone. determined. For example:  When the risk of staining is present 8.5 Test Panels. By cleaning and  As an aid in daily maintenance inspecting test panels, the Specifying Authority procedures can determine if the method is satisfactory.  Where a coating may help to preserve This procedure eliminates the possibility of the stone finish in excessively high improper cleaning; since the Owner and wear conditions Specifying Authority can see what results will be obtained prior to commencement of the  Where weathering has affected or may total contract. It also gives the Cleaning affect the integrity of the stone surface Contractor a standard to work toward, making  To prolong the aesthetic beauty of the definition of the cleaning more specific for all original installation parties.  Where the risk of graffiti or other vandalism is high. 8.6 Local Regulations. Many local municipalities have regulations related to water 10.0 STAINS AND REMOVAL use and chemical disposal. Always check these PROCEDURES regulations and authorizations before bidding on such cleaning projects; in some cases, there 10.1 Oil-based Stains (grease, tar, are additional costs associated with these cooking oil, cosmetics). An oil-based stain regulations. will darken the stone and normally must be chemically dissolved so the source of the stain 9.0 TOPICAL SEALERS AND can be flushed or rinsed away. First, remove IMPREGNATORS excess staining agent by wiping or chipping (if tar). Clean gently with a liquid cleanser, 9.1 Topical sealers are coatings household detergent, ammonia, mineral designed to protect the surface of stone against spirits, or acetone. Do not pour cleaner water, oil, and other contaminants. They are directly on the staining agent, as this can thin formulated from natural wax, acrylic, and the contaminant and further its penetration and other plastic compounds. spread. Partially saturate a paper or cloth towel with the cleaner and attempt to draw the stain 9.2 Impregnators (penetrating into the towel. Commercially available sealers). Impregnators are generally hydrophobic (water-repelling), but some are Page 21-80 • Maintenance  2016 Marble Institute of America specialty cleaners, such as alkaline degreasers 10.6 Paint Stains. Small amounts of paint and/or poultices may also be used. can be removed with lacquer thinner or scraped off carefully, using a razor blade. 10.2 Organic Stains (coffee, tea, fruit, Heavy paint coverage should be removed with tobacco, paper, food, urine, leaves, a commercial liquid paint stripper. Other bark, animal droppings). Organic stains methods to remove paint would include baking may cause a pinkish-brown stain and may soda blasting or glass bead blasting. These disappear after the source of the stain has been methods should be undertaken by experienced removed. Outdoors, with the sources professionals. Begin by testing a small area to removed, normal sun and rain action will determine the efficacy of the method. Do not generally bleach out the stains. Indoors, clean use acids or flame tools to strip paint from with 12% hydrogen peroxide and a few drops stone. Use of solvents can potentially drive the of ammonia. Commercially marketed cleaners stain further into the stone. and poultices are also available. 10.7 Water Spots and Rings (surface 10.3 Inorganic Metal Stains (iron, accumulation of hard water). Buff with rust, copper, bronze). Iron or rust stains dry steel wool. are orange or brown and leave the shape of the staining object, such as nails, bolts, screws, 10.8 Fire and Smoke Damage. Older cans, flowerpots, or metal furniture. Copper stone surfaces and fireplaces stained by smoke and bronze stains are green or muddy brown or fire may require a thorough cleaning to and result from the action of moisture on restore their original appearance. nearby or embedded bronze, copper, or brass Commercially available smoke removal items. Metal stains must be removed with a products may save time and effort. Calcareous poultice (see Section 11.0 of this chapter). stones may also require refinishing due to Deep-seated rust stains are extremely difficult etching from carbonic acid. to remove, and the stone may be permanently stained. 10.9 Etch Marks are caused by acids left on the surface of the stone. Some will etch the 10.4 Biological Stains (algae, mildew, finish but not leave a stain; others will both etch lichens, moss, and fungi): Clean with and stain. Once the stain has been removed, diluted (1⁄2 cup in a gallon of water) ammonia, wet the surface with clean water and sprinkle bleach, or hydrogen peroxide. Do not mix with polishing powder. Rub the powder into bleach and ammonia; this combination creates the stone with a damp cloth or by using a a toxic gas. There are a number of commercial buffing pad with a low-speed power drill or products available that are as effective as polisher. Continue buffing until the etch mark ammonia, bleach, or hydrogen peroxide disappears and the surface shines. Honing may without the potentially hazardous downside. be required for deep etching. This process may require the services of a professional refinisher. 10.5 Ink Stains. Clean light-colored stones with bleach or hydrogen peroxide. Use 10.10 Efflorescence is caused by water lacquer thinner or acetone for dark-colored carrying soluble salts from below the surface of stones. Do not pour cleaner directly on the the stone. The salts are deposited and staining agent. This can thin the contaminant recrystallize upon evaporation of the water, and further its penetration and spread. Partially leaving a powdery salt residue. If the saturate a paper or cloth towel with the cleaner installation is new, dust mop or vacuum the and attempt to draw the stain into the towel. powder. Repeat as necessary as the stone dries out. Do not use water to remove the powder. If the problem persists, contact the contractor

 2016 Marble Institute of America Maintenance • Page 21-81 to identify and remove the cause of the process draws the stain out of the stone and moisture. into the poultice material. After approximately 24 hours, remove the plastic and allow the 11.0 POULTICE MIXTURES FOR poultice to dry. VARIOUS STAINS 11.7 Remove the poultice from the stain. 11.1 Overview. A poultice is a chemical or Rinse with distilled water and buff dry with a mixture of chemicals combined with an soft cloth. Repeat the poultice application if the absorbent material to form a thick paste, which stain is not removed. It may take five or more is applied to stone to remove stains. applications for difficult stains.

11.2 Poultice materials include kaolin, 11.8 If the chemical etches the surface, fuller’s earth, whiting, diatomaceous earth, apply polishing powder and buff with a powdered chalk, white molding plaster, and polishing pad recommended by the polishing talc. Approximately one pound of prepared powder’s manufacturer. poultice material will cover one square foot. Do not use whiting or iron-type clays such as 11.9 Poultice Mixtures for Various fuller’s earth with acid chemicals as the Stains. chemical reaction will cancel the effect of the poultice. A poultice can also be prepared using 11.9.1 Oil-based Stains. Poultice with white cotton balls, white paper towels or terry baking soda and water or one of the powdered cloth rags, or gauze pads, which may be more poultice materials and mineral spirits or a effective when using highly volatile solvents commercial degreaser. such as acetone or mineral spirits. Premixed poultices are available in ready to use form or 11.9.2 Organic Stains. Poultice with one of require adding only water. These are available the powdered poultice materials and acetone from stone maintenance supply companies. or 12% hydrogen peroxide solution.

11.3 Prepare the Poultice. If using a 11.9.3 Iron Stains. Poultice with powdered poultice material, mix with the diatomaceous earth and a commercially cleaning agent or chemical to a paste with a available rust remover. Rust stains are thick, creamy consistency (approximately the particularly difficult to remove; professional consistency of peanut butter). If using paper, assistance may be required. Many rust soak it in the chemical and let drain. Do not let removers contain acids that will etch marble, the liquid drip. Prepare stain area. Wet the limestone, and certain granites. stained area with distilled water. 11.9.4 Copper Stains. Poultice with a 11.4 Apply the poultice to the stained area powdered poultice material and ammonia. about 1⁄4" to 1⁄2" thick, and extend the These stains are difficult to remove; poultice beyond the stained area by about 1". professional assistance may be required. Use a wood or plastic scraper to spread the poultice evenly. 11.9.5 Paint Stains (water-based). Poultice with a powdered poultice material and 11.5 Cover the poultice with plastic and a commercial paint remover. tape the edges to seal it. Punch several small holes in the plastic to allow vapor to escape. 11.9.6 Paint Stains (oil-based). Poultice with a powdered poultice material and mineral 11.6 Allow the poultice to dry thoroughly; spirits. Deep stains may require methylene this usually takes 24 to 48 hours. The drying chloride. When using highly volatile solvents in

Page 21-82 • Maintenance  2016 Marble Institute of America poulticing, use a paper towel, pouring the  Building and property boundaries solvent on the paper towel and then placing the towel on the stained area. 12.3 Repointing, Sealing, and Replacement. Specify if repointing or re- 11.9.7 Ink Stains. Poultice with a powdered sealing of joints and replacement of stone are poultice material and mineral spirits or included in the cleaning scope of work. methylene chloride. When using highly volatile solvents in poulticing, use a paper towel, 12.4 Related sections are to be pouring the solvent on the paper towel and determined by design requirements. then placing the towel on the stained area. 12.5 Requirements. 11.9.8 Biological Stains. Poultice with a poultice material and diluted ammonia, bleach, 12.5.1 General requirements include the or hydrogen peroxide. Do not mix ammonia plans, general conditions, supplementary and bleach; this combination creates a toxic general conditions, and the executed gas. agreement.

11.10 Flammable Materials. The 12.5.2 Certified statements must be preceding text does not address possible safety furnished as required, attesting that all concerns associated with the use of flammable materials to be used meet the requirements solvents. Refer to the manufacturer’s labeling specified and approved. and MSDS for further direction in the safe handling and use of these products. 12.5.3 Scheduling. Provide Specifying Commercially available cleaners exist for Authority with schedule of cleaning operations remedy of many common stains. These indicating time of day work will be performed. cleaners may have fewer health and safety Wet cleaning methods should not be concerns. Always use appropriate Personal performed when temperatures reach 35°F or Protective Equipment (PPE) when handling lower. solvents or other chemicals. 12.5.4 Test Areas. For approval by 12.0 SPECIFICATIONS FOR Specifying Authority, clean at least a 4’x4’ test BUILDING CLEANING area for each type of soiling, stone variety, and finish requiring cleaning. Test panels should 12.1 Introduction. This section pertains include intersection of horizontal and vertical to the furnishing of all labor, materials, joints. The approved panel(s) should be the equipment, and services necessary for the standard for cleaning methods and finish of all complete cleaning of exterior building stone as areas to be cleaned. indicated on the plans and described in the specifications. 12.5.5 Protection. For approval by Specifying Authority, provide material types 12.2 Information to be shown on drawings: and methods to protect adjacent materials and  Location, size, and area or items to be surfaces from damage, moisture, and staining. cleaned If other refurbishing operations are being  Location, size, and number of test conducted, protect cleaned stone areas with an panels approved non-staining covering.  Areas not included in cleaning 12.5.6 Cleaning. After the surface has been  Location, size, and description of cleaned, rinse with potable water applied to materials requiring protection

 2016 Marble Institute of America Maintenance • Page 21-83 the temperature and pressure of the municipal Chemicals can be dangerous to the stone, the water supply. technician, and the surrounding landscape. Therefore, all chemicals used must be tested 12.6 Materials. Water should be potable, and monitored. non-staining, and free of materials detrimental to the surface being cleaned. 12.7.5 Acids. Chemicals with a pH below 7 should not be used on calcareous or dolomitic 12.7 Methods to be determined by stones. approved test areas. 12.7.6 Alkalis. Chemicals with a pH above 7 are safe for use on most stones. These are 12.7.1 Hydraulic. Water at varying usually followed with a mild acid wash to pressures between 300 and 600 psi and at neutralize the alkaline salts. municipal supply temperatures shall be jetted against the surface to be cleaned. Care must be 12.7.7 Neutral Cleaners. Chemicals exercised in selecting nozzle tip degree; zero containing surfactants with a pH equal to 7 are nozzle tips should never be used. safe for most stones.

12.7.2 Water Misting. Clean the surface 12.7.8 Solvents. Waterless chemicals, such with water. Misting heads are set up on as mineral spirits and acetone, are rarely used scaffolding and water is misted onto the surface for building cleaning due to their high of the building. The misting heads may be set flammability. on a timer so that they go on and off intermittently. The intermittent cycle allows 12.7.9 Bacteria. Special bacteria can be the building to dry and prevents oversaturation applied to “eat” dirt and salts. of the stone. This method is the safest for 12.7.10 The J.O.S. system for removal cleaning and is widely used on historical of dirt and graffiti uses a low-pressure washer buildings. and milled glass or dolomite powder. Pre-

12.7.3 Pressure washing employs the use rinsing is required. of high-pressure water jets of up to 2,500 psi 12.7.11 Dry cleaning uses organic or more. Pressure washing works by blasting powder or mineral powder (aluminum silicate) the dirt off the surface of the stone, and can crystals sized between 10 and 90 micros. cause irreversible damage to the stone surface. Pressure washing can be an effective and 12.7.12 Sandblasting is an extremely efficient means of removing dirt and other aggressive method of cleaning and should only contaminants. Modern pressure washers can be considered when believed to be the only produce pressure in excess of 2,500 lbs/in², effective solution. Soda blasting (using baking which can permanently damage many stone soda in lieu of sand) is generally not as types. Maximum allowable pressure should be destructive and has some limited usage in the determined by slowly increasing pressure cleaning of natural stones. while testing in an inconspicuous area. In no case is pressure in excess of 1,000 lbs/in² 12.8 Safety Requirements. All of the recommended, and usually much less pressure methods listed above require specialized is appropriate. Always use a fan-tip spray equipment. Adherence to OSHA safety nozzle. Only highly trained technicians should requirements by highly skilled technicians is employ this method. mandatory.

12.7.4 Chemical cleaning is used in 12.9 Testing. All methods must be tested combination with one or several of the water for potential damage to the stone. washing methods to dislodge soiled particles.

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COMMERCIAL AND traffic,” making “efficiencies of scale” more important for these projects. HISTORIC restoration 2.3 Levels of Pedestrian Traffic. Pedestrian traffic rates in most commercial settings will generally be much greater than 1.0 INTRODUCTION those encountered in residential settings. The 1.1 When compared to residential amount of abrasive particles (dirt and grit) restoration, commercial and historic stone introduced to the stone surface via footwear is restoration poses several unique requirements also substantially greater. These abrasive and challenges. While many underlying particles can do significant damage to most techniques in residential restoration are stone finishes, particularly in the softer stone applicable to commercial projects, changes varieties. must be made to adapt to a more complex nature. Commercial and historic stone 2.4 Challenges Encountered With restoration both require a strong Site Access and/or Restrictions understanding of laws and regulations to protect the integrity of the structure as well as 2.4.1 Work Platforms. Vertical surfaces to avoid fines and/or citations. Further in commercial applications can extend to great challenges arise due to the scale, intensity, heights, often necessitating the use of work location, traffic patterns and management of platforms beyond ladders. Scaffolding, scissors these projects. This section will cover most of lifts, and even mast climbers or suspended the common requirements and challenges scaffolding may be required to gain access to associated with commercial and historic commercial facades. The use of these and other restoration. For the purposes of this document, equipment requires knowledge of OSHA the term “restoration” will include cleaning, regulations, local ordinances (right-of-way refinishing, repair, sealing, and maintaining. permits), and common sense safety knowledge. All workers using elevated work 2.0 DIFFERENCES platforms must be trained in the safe use of the equipment and the health and safety regulations 2.1 Rules and Regulations. On any that govern its use. commercial or historic project, it is absolutely necessary to familiarize oneself with and follow 2.4.2 Existing lighting in commercial all federal, state, and local regulations and spaces may be insufficient for restoration requirements. Regulations are in place for work, or may be on automated switches that worker protection and public safety. cannot be overridden by onsite restoration Noncompliance with these mandates is not mechanics. The restoration contractor is only dangerous and unprofessional, but can usually best served by providing his/her own result in substantial fines. The most common lighting equipment to adequately illuminate sources for these regulations in the U.S. are the the work area. Occupational Safety and Health Administration (OSHA) and the U.S. Department of the 2.4.3 Electrical Power. It must be verified Interior, through the National Park Service that adequate electrical power is available (both (NPS). required voltage and amperage). If this is not the case, the cost of providing generators must 2.2 Size of Project. The size of lobbies be taken into consideration. or commercial spaces are typically larger than residential spaces, with significantly more “foot 2.4.4 Water Supply. If an adequate quality and quantity of water is not available onsite,

 2016 Marble Institute of America Commercial and Historic Restoration • Page 21-85 considerable cost will be encountered in mandated accessibility guidelines, staircases are bringing water from on outside source. rarely the only access point to a floor, so alternate means of access can usually be 2.4.5 Water Discharge and Disposal. It arranged while the staircase is being restored. must be verified if water discharge and disposal can be accomplished onsite, or if spent water 2.5.3 Vertical Surfaces (interior and supply and/or slurry must be removed from exterior). It is far more common to the site. This is just as important as verifying encounter expansive vertical surfaces in water supply. commercial projects than in residential projects. In addition to general soiling, these 2.4.6 Hours of Site Access. Many surfaces can be abused by other construction commercial restoration projects require that trades, delivery equipment, improper cleaning the work is performed when the building is methods, snow removal equipment, or signage unoccupied or at a reduced level of occupancy. and decoration mounting. It is important to This may require working at night or on the eliminate the source of abuse to the surface weekend. Ensure that onsite workers have prior to restoration, otherwise the damage will access to the restoration company’s simply reoccur after the stone is restored. management personnel, safety managers, and building managers while working during these 2.5.4 Special Features (stone trim such non-traditional hours. as base, plinth blocks, jambs, casings, etc.) are not subject to normal foot traffic, but 2.4.7 Maintaining Occupants’ Access can still take abuse from getting hit with carts, during Working Hours. Work areas may vacuums, floor scrubbers and other items. be limited in certain projects so that access can Restoring specialty features can be very time be maintained. For example, if the restoration consuming and the required hours can be includes the elevator cab floors in a hotel, it difficult to estimate in the bidding phase. may be necessary to do one elevator at a time Additionally, these features are by design a so that the other elevators remain functional, “focal feature,” so the customer’s demands of even in off-peak hours. the quality of the restoration efforts may be elevated. 2.5 Unique Features Found in Commercial Buildings 2.5.5 Multi-component Surfaces. Surfaces that include different materials such as 2.5.1 Revolving Doors. In most cases a metal dividers, carpet, wood, or even stones of revolving door is not the only entrance to a differing hardness present an additional building, so the revolving door area can be challenge to the restoration professional. worked on while occupants are given an Protection of the various components becomes alternate, temporary entrance to the building. the responsibility of the restoration The doors can be collapsed or removed to professional. Refer to the Restorative increase access to the workspace during Processes section (p21-xx) for more restoration. Pending weather and location of information on how to handle multiple the project, varying levels of temporary surfaces. building enclosure may be required over the area until the revolving doors can be replaced. 3.0 MAINTENANCE HISTORY AND PRODUCTS USED 2.5.2 Staircases are common in commercial and historic restoration projects. 3.1 Janitorial staffs of commercial Smaller equipment is normally utilized, and the buildings may be employees of the building production rate is greatly reduced. Due to owner, a building tenant, or a subcontractor.

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Varying levels of stone care knowledge and competent restoration contractors may use experience exist amongst janitorial staffs and these products to cover up processes that were supervisors. Those with higher knowledge and not performed properly. Due to the topical experience levels, particularly when willing to coverage and prohibition of both fluid and research the unique maintenance needs of the vapor transmission, these products can actually stone product, are undoubtedly more damage the stone. However, since these successful in keeping building owners and products form a sacrificial layer above the occupants satisfied with the appearance and stone’s surface, there are unique exposure performance of the stone products. Refer to conditions where they may be recommended. DSDM Chapter 9 (Maintenance) for more information on this topic. 4.0 LABOR RESTRICTIONS

3.1.1 The restoration professional is often 4.1 Unions. Commercial restoration responsible for instructing the janitorial staff on projects frequently mandate that the work be required techniques and products to use after performed by union personnel. Check all the stone has been restored. In these cases, it is union regulations, including pay scales, often easier to instruct a staff with little or no benefits, and staffing requirements prior to stone care experience, which eliminates the bidding to ensure that adequate funding exists need to change the bad habits previously used to comply with the unions’ requirements. It is by the staff. possible, depending on the nature of the work, that more than one union will have jurisdiction 3.1.2 The restoration professional is usually over parts of your scope of work. best serving the client by encouraging them to contract with experienced, competent stone 4.2 Federal Projects. Most federal jobs maintenance providers for their daily or require certified payroll reports. This report weekly maintenance needs. This usually proves show which days were worked, labor to be a wise investment for facility managers classifications of the workforce, and rates of and owners that want to protect their stone pay. investment. 4.2.1 Labor Classifications and 3.2 Maintenance Products Education. All labor classifications and corresponding pay scales must be met. 3.2.1 Topical sealers and/or coatings. Maintain records to verify compliance in case Long-term waxes, sealers, epoxy coatings, and the project is audited. other topcoats are more common in older lobbies, when topcoats were the preferred 4.2.2 Confusion Regarding option. These coatings must be removed prior Classifications and Pay Scales. In some to restoration of the stone surface. cases, it may be difficult to find an exact match Identification of the product is usually of job descriptions in federal documents to necessary to ensure that the removal and accurately determine the correct pay rates. If disposal of it is done in a safe, environmentally doubt exists, contact the agency involved for friendly, and legal manner. Refer to DSDM their input. Maintain records and document all Chapter 9 (Maintenance) for more information conversations in case a dispute develops at a on this topic. later date.

3.2.2 Short-term Coatings or Waxes. 4.2.3 Report Filing. Frequency of filing Stone maintenance and restoration may vary from weekly to monthly. Determine professionals do not advocate the use of these the frequency required and comply with the products, except in extremely rare cases. Less reporting requirements.

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4.2.4 Other Restrictions. Federal be high, since they are usually all property Department of Interior Standards must be owners in the complex. followed. This requires a thorough knowledge of various restoration disciplines and an 5.3.2 Historical Review Committees aptitude for report writing. Information on this will be encountered any time work is done to can be found in section 12 of this chapter a project that is deemed to have some level of (Additional Learning Resources). historical significance.

5.0 GETTING APPROVAL FOR 6.0 MANAGING WORK PERFORMED PERFORMANCE

5.1 Customer satisfaction is the 6.1 Large commercial restoration projects ultimate goal. In order to achieve this goal, it is may have extremely long durations. Progress necessary to communicate the proposed and expenses must be tracked throughout the improvements accurately. Test patches, project to ensure that the anticipated mockups, and samples will help with this profitability can be achieved. Discuss the labor communication. Ideally, test areas or mockups and material requirements with the job should remain in place until the balance of the foreman or superintendent at the beginning of work is completed to serve as a benchmark of the project and revisit these requirements acceptance. frequently.

5.2 Single Person Responsibility. It is 7.0 FUNDING, BILLING, AND typically easier to communicate with and COLLECTING satisfy one person, such as a maintenance supervisor or facilities manager, who may have 7.1 The process of payment on a the sole authority to accept or reject the work commercial or historic project can be different of your crews. Additionally, if a problem or than on a residential project. Sometimes question arises, this person can usually be payment will only be considered if the request included in the problem solving and decision is submitted on the responsibly party's form. making processes. Payment can also depend on the tax and restoration parameters allowed by the 5.3 Boards and Committees. When Historical Review Board, various funding the contracting and acceptance of the work is procedures and taxes. Every state usually has a decided by a board or committee, it may be historical society, committee, or department difficult to achieve consensus within the group, in charge of maintaining and preserving since the individuals comprising the group may historical landmarks. Depending on the have differing standards, perceptions, and historical structure or place, there may be experiences. It is a good practice to meet with available tax credits to help offset the costs of the group prior to submitting your proposal. restoration or repair. The National Register of This will allow you to learn of their exact Historical Places, which is administered by the expectations and provide an opportunity to National Park Service, gives status and possible discuss of how these how these expectations tax credits and funding for significantly may impact the cost of the project. historical structures.

5.3.1 Commercial Committees. One of 8.0 ADDITIONAL RESOURCES the most common committees encountered in commercial work is the “condominium board,” 8.1 See the last section of this chapter for when doing work in a condominium complex. Additional Learning Resources. The emotional investment of its members may

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TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference Consult with structural engineer for remedial Photo 53, Cracking, alignment, Structural settling or suggestions. Replace tile or clean, prep and All All Natural stones Photo 75, and grout distress instability repair tile and refinish as necessary to smooth Photo 127 out repair.

Clean, prep and use a penetrating or flowing epoxy to bond though the stone. Next use a Fractures caused by material knife grade epoxy with the correct color tint if handling, substrate All Cracks in Slabs All Natural stones needed. For outdoor repairs, use a UV stable, Photo 121 deformation, or vibration two part epoxy with the correct color tint. For from field cutting. white marble and porous limestone, preseal to keep the resin from bleeding into the stones.

Exfoliation occurring either to poorly cemented minerals Clean, prep, and fill with a clear or a custom Photo 37, Exfoliation of Minerals or minerals that have been colored epoxy. The stone may need to be Photo 38, All All Natural stones at face of stone loosened by expansions, resurfaced. If stone is resurfaced, apply Photo 47, mechanical stress, or appropriate impregnating sealer. Photo 72 freeze/thaw cycling.

Photo 68, Spall (chips or splinters Lack of vapor transmission at Remove coatings that block stone’s ability to Photo 80, All separated from the All Natural stones stone's surface. breathe. Photo 84, main mass of a stone) Photo 128

Clean, prep and use a penetrating or flowing epoxy to bond though the stone, then a knife Natural seams in the stone grade epoxy with the correct color tint if needed. that have fully opened to be All Fissures All Natural stones For outdoor repairs, use a UV stable, two part Photo 43 considered a crack or epoxy with the correct color tint. For white fracture. marble and porous limestone, preseal to keep the resin from bleeding into the stones.

Gray colored stain Stone was installed using Light colored Remove and replace - only white thinsets may All bleeding through light gray colored portland based calcareous stones be used with light colored calcareous stones. stone thinset

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Occasional small holes (taroli , in Italian) and voids Clean, prep and fill holes with color matched All Pin Holes Marble are to be expected, and are Photo 15 epoxy. characteristics of Soundness Classification B marbles.

On light colored stones, clean with bleach or hydrogen peroxide. On dark colored stones, All Ink Stains All Natural stones Ink pen or marker stains. clean with lacquer thinner or acetone. Do a test in an inconspicuous area to make sure this is the correct method. Numerous, possibly hundreds of small pits in the Clean and prep as best as possible and fill with All Pits Limestone Photo 59 stone visible with certain CA glue, or color matched polyester acrylic. lighting. If possible, identify the stain origin, then poultice with appropriate poultice recipe. If stain origin Random stains caused by cannot be identified, several trial and error Photo 7, All Random Stains All Natural stones known or unknown staining MIA’s book on Poultice attempts may be necessary. Multiple Photo 101 agents. applications of poultice may be required to fully eradicate the stain.

Review manufacturer's application instructions Dark spots remain Sealer did not fully penetrate to ensure proper application methods are being All after water wiped from All Natural stones stone due to improper used. Allow full cure time between applications. Photo 64 stone. application. Use multiple applications until desired performance is achieved.

This is usually the result of too much detergent or Clean with a heavier cleaner for stone and hot Sticky or Clouded All All Natural stones cleanser being used during water. For hair spray on marble, use a safe HD Photo 44 Surface normal cleaning cleaner with a white pad. maintenance.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Identify the sealer that was used, then try to re- emulsify with the same sealer with a white or hog's hair pad by breaking the surface tension Streaks or haze in cured Streaking or Haziness and then wipe it up and buff it out. Or use Photo 74, All All Natural stones sealer cannot be cleaned from Sealer Mineral Spirits and again break the surface Photo 78 with regular cleaners. tension. Or use a safe alkaline stripper and break the surface tension, wipe off and buff out. If unsuccessful, then stone must be refinished.

Swirl marks in the stone surface are generally caused Start refinishing from the least abrasive diamond by equipment malfunctions grit until you can successfully remove the swirl All Swirl Marks All Natural stones or operator errors in the Photo 40 marks, then proceed to finer grit sizes until the original fabrication of the desired gloss level is achieved. stone or in a previous restoration attempt.

Dark banding visible in the stone surface is frequently residual adhesive from tape that had been applied and removed. Some tapes have Use acetone with a white nylon pad and rub mildly acidic adhesives, vigorously. Multiple applications may be which are more prone to Photo 42, All Tape marks All Natural stones required. If unsuccessful, diamond grind the surface damage of Photo 51 areas and then refinish to desired level of gloss. calcareous stones. Extended Some "feathering" and blending will be required. dwell time on the stone surface, and exposure to sun or other heat source also increase the likelihood of tape marks.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Countertop settling Clean with acetone and a white pad vigorously. - edge not polished It the stain does not go away, diamond grind to factory polish - until the residue is gone, then bring back to the correct: break the Dark lines, usually dull, and Photo 71, All Tape Residue factory shine. (Note: tape adhesive may have seam, relevel the often showing dirt collection. Photo 51 penetrated significant depth of the stone, which tops with proper can make the lines reappear if color enhancer is support and polish used). the edges

Small amounts can be removed with lacquer thinner or scraped off carefully with a razor blade. Paint strippers can be effective but may etch some stones. Follow the manufacturers' directions for use of these products, and flush the area thoroughly with clean water. Use appropriate PPE when using these chemicals. Usually this can be identified All Topical, colorful stains All Natural stones Use only wood or plastic scrapers for removing as paint. the sludge and curdled paint. Normally, latex and acrylic paints will not cause staining. Oil- based paints, linseed oil, putty, caulks and sealants may cause oily stains. Refer to the section on oil-based stains. (In short, a good quality colloidal cleaner is probably the best and safest solution.)

Yellow-to-orange staining Rust poultice will be required Most rust can either be from ferrous poultices are acid based and will etch calcium- content indigenous to the carbonate based stones, so refinishing will be stone fabric, or from an necessary after the rust treatment. Quick rust Light colored Photo 95, All Yellowing outside source, like a metal treatments can be less damaging to the stone Natural Stones Photo 96 container or object in but the purple stain left from improper use of contact with the stone, or a some products can be fixed with 20-30% fastener corroding beneath hydrogen peroxide. Testing in an inconspicuous the stone. area should be done before the final application.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Clean, prep, and fill chips with a polyester epoxy with a custom tint or CA Glue. For outside chips you will need a UV stable two part epoxy with a Chips occurring from impact custom color tint. For white marble and porous Countertop Chipping due to impact All Natural stones by pots, pans, and other Photo 79 limestone, preseal to prevent any bleeding from hard objects. the resin in the two part epoxy. In some cases you may need to drill small holes into the chip to get better tooth or bite.

Use a poultice (a blend of clays) with hydrogen Food, and specifically fruit peroxide (20%). Use nitrile gloves and safety and fruit juices, like grape goggles when using this product. Sometimes a juice, wine, coffee, Countertop Colored Stains All Natural stones mild bleach solution will take stains out. vegetables, tea, and even Neutralize the beach after use with water mixed grass and mud create with a neutral cleaner. Calcareous stones may different colored stains. etch and the surface may need to be refinished.

Wiping with a towel saturated in mineral spirits Dark areas around will usually be effective, although many Countertop fixtures and/or soap All Natural stones This is obviously a soap stain. Photo 101 applications are usually required. Denatured dispensers alcohol is also sometimes effective.

Resin, color enhancer, or Countertop Change or faded color All Natural stones sealer not 100% UV Refinish; use UV resistant resin/ color enhancer. Photo 4 resistant.

Use a poultice with the correct additive in the Photo 8, blend of powder or a good, ready-to-use Photo 41, Dark colored stains are Countertop Dark Stains (Oil) All Natural stones poultice liquid. Follow manufactures' directions. Photo 100, frequently oil based. This may have to be done over weeks or months Photo 101, until the stain is gone. Photo 102

Regrind with coarse grits and then bring the Photo 12, Granite, Marble, Substandard edge polishing Countertop Dull Edges surface back to a factory shine using Photo 13, Limestone on original material. progressively finer grits. Photo 14 The edges are fuzzy and not Diamond grind surface and repolish back to the Countertop Dull or Clouded edges All Stone Types Photo 63 even. desired gloss level.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference Areas are dull and have Diamond grind surface and repolish back to the Photo 45, Countertop Dull Spots or Rings Marble reduced gloss due to mild desired gloss level. Photo 110 etching. Dull areas around grout due All Calcareous Diamond grind surface and repolish back to the Countertop Etched areas to inappropriate (acidic) Photo 104 Stone Types desired gloss level. grout cleaner. Clean the copper stain with a very mild acid. Neutralize and you have to resurface the stone Green-to-blue Colored Green-to-blue colored stains Photo 18, Countertop All Natural stones back to its original state. If the stain remains, a Stains are usually cuprous in origin. Photo 28 poultice may be need with the correct additive for the stain.

Hard water deposits are usually caused by a combination of high mineral Carefully use single edge razor with mild soap to Hard water deposits Countertop All Natural stones content water supply and remove buildup from counter top, or remove the Photo 22 near faucet fixtures occupants allowing the fixtures and refinish. water to puddle, unwiped, on the countertop surface.

This is typically indicative of a slab that has been "rodded," meaning that a reinforcement rod had been If you can open the stone carefully, pull out the embedded into the metal rusted rod, using a two part UV stable underside of the slab at this epoxy with the correct color tint and glue it back Photo 29, location. If a mild steel rod Linear Crack at front of together and top polish the next day. If the Photo 30, Countertop All Natural stones has been used, and if the sink location crack is too small to get any penetrating glue in, Photo 76, fabricator did not you might want to wait till it opens further. If Photo 99 successfully fully encapsulate unrepairable, the only remedy is replacement of the rod in epoxy, corrosion the countertop. can occur. The swelling of the rod due to corrosion can create enough pressure to crack the stone slab.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Break the seam if possible. Use a seam setter to level the two slabs and apply a flowing epoxy DSDM, COUNTERTOPS: Lippage on One stone slab is higher than Countertop All Natural stones followed by a knife grade epoxy with the correct TOLERANCES -Lippage Photo 17 Countertops adjacent slab. color. Or diamond grind the high slab to match Section the other slab, and then refinish to original gloss.

All true granites contain a micaceous mineral called "biotite," which is a black colored mineral of "flakey" or layered construction. Fill pits with CA adhesive and when cured, Countertop Mineral Pitting Granite During the polishing process, scrape with a razor in multiple directions until Photo 35 biotite can be "plucked" the filler matches the plane of the stone surface. from the stone fabric by the abrasive heads of the polishing machine, leaving a shallow pit in the surface.

Whitish rings or spots occurring on black granite (which technically are not granite) have often been blamed on dyes used in the stone. While this is possible, it is not as common as believed. These materials may have complex Either refinish starting with very fine grit, or buff Countertop Rings or Spots Granite Photo 3 mineralogy including with a pad. minerals that are not traditionally included in true granites. Calcium-carbonate based minerals and clays can be present in these materials, both of which can change color due to wet/dry cycling.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference Verify that it is a stain and not an etch. True Commonly caused by the granite can be cleaned with acidic cleaners. Rings or Spots on Countertop All Natural stones stone's reaction to ponded Calcareous stones must be resurfaced. These Photo 106 Outdoor counters water on the surface. marks will usually reoccur if the exposure is unchanged. Deep clean all smoke stains (if needed) with an Staining, discolored sealer, alkaline cleaner or mild acid, (5-6 on the pH Surface staining from soot, or other stains from scale). Diamond grind and polish back to desired Countertop All Natural stones Photo 16 heat source heat source such as fireplace gloss. Grinding may be required to significant or cooktop. depth if stone has been etched due to carbonic acid. Stone had originally been Photo 85, Countertop White Rings Granite dyed (normally black Attempt to re-dye to stabilize color. Photo 86 stones). Sealer did not fully penetrate Remove sealer with an acidic marble polishing Countertop White Rings Granite Photo 3 stone. compound. Moisture reacting with ANSI A118.10 Stop source of moisture & resurface stone, Flooring Blistered Surface Granite minerals in stone (this can be TCNA F122 Stone Photo 36 refilling as necessary. confused with spalling). or F121 Stone Usually caused by Blotchy, Uneven nonuniform application as a Strip the enhancer off and then start over. In Flooring appearance in Color All Natural stones result of the floor being wet Photo 61 some cases, refinishing will be required. Enhanced Floor when the color enhancer was applied.

Clean, prep and use preferably a slow curing Corners are broken, usually epoxy with a custom color to rebuild the as a result of heavy rolling corners. Following cure of the epoxy diamond Flooring Broken Corners All Natural stones loads over corners that have Photo 19 grind and refinish to desired gloss. A polyester no support due to voids in resin (fast curing) can also be used, but does not the setting bed. have the performance of the epoxy.

Flooring Cracking Granite Improper substrate Replace tile. Photo 31 Flooring Cracking Granite Deflection issue Check joist size, spacing & span. Photo 31 Lack of crack Replace tile and utilize crack isolation Flooring Cracking Granite isolation/suppression membrane. membrane.

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference Seams in cement board not Flooring Cracking Marble Tear out and replace. ANSI 108.5 filled.

Flooring Cracking Marble Improper adhesive coverage. Tear out and replace. ANSI 108.5 Photo 27

Insufficient joint width at Flooring Cracking Marble change of plane or other Saw out and open joint with cosmetic repair. TCNA EJ171 region of discontinuity. Replace tile and implement correct installation Photo 1, Flooring Cracking Marble or Granite Improper substrate. TCNA F250 Stone method. Photo 10 Flooring Cracking Marble or Granite Excessive deflection. Check joist size, spacing and span. TCNA F250 (Optional) Lack of crack Replace tile and utilize crack isolation TCNA F125 Stone Flooring Cracking Marble or Granite isolation/suppression Photo 27 membrane. (Concrete) membrane.

Use appropriate adhesive, reset with a minimum Photo 9, Lack of bonding adhesive Flooring Cracking Slate 95% of coverage with the mortar. Many times ANSI 108.5 Photo 107, under the tile. the stone can be reused. Photo 108

Flooring Cracking Slate Lack of expansion joints. Tear out and replace. TCNA EJ171, F250 Stone

Lack of bonding adhesive Flooring Cracking Travertine Replace broken tile. ANSI 108.5 Photo 23 under the tile.

Flooring Cracking Travertine Lack of expansion joints. Tear out and replace. TCNA EJ171, F250 Stone

Lack of alkaline resistant Flooring Cracking Travertine Tear out and replace. ANSI 108.5, TCNA EJ171 mesh tape. Difference between Usually this is due to color Carefully strip off the wax, neutralize with water Photo 56 Flooring covered areas and All Natural stones change as a result of UV and refinish. Photo 55 exposed exposure of a wax. Polishing compound used Photo 125 Flooring Dimpled appearance Travertine, Marble too hot resulting in 'orange Grind and refinish to original surface quality Photo 124 peel'

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Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Identify the sealer that was used, then try to re- Foot prints can be seen in emulsify with the same sealer with a white or certain lighting conditions in hog's hair pad by breaking the surface tension the sealed floor, but cannot Foot Prints in Sealed and then wipe it up and buff it out. Or use Photo 118 Flooring All Natural stones be cleaned with regular Stone Mineral Spirits and again break the surface Photo 119 cleaners due to floor having tension. Or use a safe alkaline stripper and break been walked on prior to full the surface tension, wipe off and buff out. If cure of the sealer. unsuccessful, then stone must be refinished.

Insufficient accommodation Cut grout joints and replace with appropriate Photo 26, Gaps in stone or Flooring All Natural stones for thermal expansion and movement and/or expansion joint detail per TCNA EJ171 Photo 70, corners contraction industry standards. Photo 105

Excessive and non-uniform depth of thinset over a Remove and replace, using proper floor leveling Photo 10, Flooring Indent Fractures All Natural stones membrane, creating uneven TCNA F141 techniques and controlled thinset depth Photo 11 shrinkage and suction upon cure MIA Design Manual, Either remove the tile and set a new one in place HORIZONTAL SURFACES One stone unit is higher that with correct alignment, or diamond grind the – LIPPAGE adjacent unit (Note: 1/32", Flooring Lippage on Floors All Natural stones high tile to match the elevation of the Photo 73 or 0.8 mm is acceptable surrounding tiles and refinish to achieve desired TCNA Handbook, tolerance). level of gloss. Lippage in Natural Stone Installations

Lack of drainage mat and/ or Tear out required to totally correct the problem. Flooring Loose Tiles Slate TCNA F122 Stone waterproofing. Many times the stone can be reused.

Use appropriate adhesive to rebond and minimum 95% of coverage with the mortar. Flooring Loose Tiles Slate Oil content present in slate. ANSI A118.4 Photo 6 Apply a burn coat or scratch coat on the back of the tile. TCNA Handbook, ANSI Insufficient contact between Achieve minimum of 95% of coverage on the 108.5 3.3, Flooring Loose Tiles Granite Photo 39 adhesive and stone. bonding mortar (Dry & Wet Areas). TCNA F102 Stone, ANSI 108.5.3.3

© 2016 Marble Institute of America Page 21-98 TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference TCNA EJ171 Flooring Loose Tiles Slate Lack of expansion joints. Implement expansion joints. ANSI 108.1

Presence of bond breaker on Flooring Loose Tiles Slate Remove bond breaker prior to repair. TCNA F122 Stone concrete slab or substrate.

Grout has eroded due to Missing grout or normal service exposure, but Thoroughly remove all cracked grout and either Flooring All Natural stones Photo 24 caulking no other signs of distress re-grout or caulk with appropriate joint sealant. exist. Excessive moisture in Open the grout and allow to dry or use a Picture Framing after bedding layers wicks into Flooring All Natural stones commercial dehumidifier to remove the ANSI A108.5 Photo 34 installation edges of stone, creating a moisture. darkened perimeter. Plastic Look; Orange Flooring Marble Over crystallization. Grind and refinish to original surface quality. Photo 125 Peel Carefully remove the excess grout with the Stones were not properly proper cleaner for grout or a razor blade with Flooring Smeared Grout All Natural stones masked or cleaned during ANSI A108.10 Photo 126 soapy water to cut down any possible scratching original grouting. the surfaces.

Stone has lost its color (outdoor application) due to Use enhancer or a colored tint with the Flooring Stone Discoloration Granite fading of dyes that were enhancer per manufacture's directions. applied to original material.

Inadequate movement and/or expansion joints, Remove and replace affected stone, adding Flooring Tenting All Natural stones causing compression in floor movement and/or expansion joints per industry TCNA EJ171 Photo 98 surface to raise, or "tent" recommendations. two or more courses of tile.

© 2016 Marble Institute of America Page 21-99 TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

This is referred to as "Indent fracturing," and is caused by All stone, White, random non-uniform shrinkage of Replacement is the only remedy, with attention specifically soft Photo 87, Flooring direction lines in face thinset that has either been paid to proper slab leveling prior to installing marble and Photo 88 of material used too thick, or too replacement tiles. limestone. uneven, and typically over a membrane.

Carefully strip off the wax, neutralize with water and diamond grind, then refinish the floor to Yellow-to-brown Photo 54, All calcareous Residual wax on stone achieve desired level of gloss. Do a small test Flooring blotchy surface on Photo 55, stone types. surface. area in an inconspicuous area prior to starting floors. Photo 56 balance of work. NOTE: Black or brown stripping pads can hone and open the softer stones.

Carefully strip off the wax, neutralize with water and diamond grind, then refinish to achieve Yellow-to-brown All siliceous stone Residual wax on stone desired level of gloss. Do a test in an Flooring blotchy surface on types. surface. inconspicuous area before starting balance of floors. work. NOTE: Black or brown stripping pads should not hurt the stones. Lime from mortar has Clean all surfaces with acidic cleaner and refinish Calcium deposits on leached through to the Paving All Natural stones if necessary. Eventual failure is likely unless a TCNA F103B Photo 2 stone surface. surface as a result of the method of bed drainage can be accomplished. repeatedly saturated bed.

Repeated saturation and/or Temporary correction can be achieved by Erosion or excessive freeze/thaw cycles of grout surface cleaning the resultant staining and Paving All Natural stones TCNA F103B Photo 2 cracking of grout. due to ponding as a result of regrouting, but eventual failure of the system is insufficient surface slope. nearly a certainty if not replaced.

Internal expansions within Clean up the loose pieces and then sand down the stone fabric either due to the edge if it is a tripping hazard. Blend and freeze/thaw cycling or feather with a brown and a black hypo pad (wet Photo 50, Paving Flaking Slate, sandstone minerals with expansive is better). Then dry and check for correct Photo 103 behavior in a saturated appearance. If too much breaks off, replace the state. tile or slab.

© 2016 Marble Institute of America Page 21-100 TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference

Lifted tiles and Remove the stone, clean the substrate and the Moisture trapped below Paving extensive grout All Natural stones back of the tile and then re-bond them using a Photo 116 surface layer. cracking. hard scratch coat on the back of the tiles.

Temporary correction can be achieved by Photo 113, surface cleaning the resultant staining, but Paving Ponding Water All Natural stones Insufficient surface slope. TCNA F103B Photo 114 eventual failure of the system is nearly a Photo 120 certainty if not replaced.

Surface cleaning of the stone will provide Usually caused by Water staining on temporary cosmetic improvement, but Paving All Natural stones inadequate, or reverse pitch, Photo 103 exterior stairs. permanent remedy can only be accomplished by of treads. removing and re-setting stones.

This is usually caused by a Remove stone and re-set with proper slope. Corner area of shower Photo 5, Showers All Natural stones flat, or reverse sloped area Check that membrane has proper slope and that floor is dark. Photo 48 that does not drain properly. dry-pack has adequate lateral transfer capability.

Dull areas due to use of All calcareous Diamond grind surface and repolish back to the Showers Etching in showers. inappropriate (acidic) Photo 52 stone types. desired gloss level. cleaner. Extremely warped or Some limestone, Selected stone was not Showers exfoliated stone in wet travertine, and appropriate for wet area Remove and replace. Photo 84 area. onyx. exposure. Test section with rust removing poultice. Current TCNA Faint rust colored Repolish surface as necessary. Seal stone with Handbook, Natural Light colored Ferrous content indigenous Photo 46, Showers stains in shower or appropriate impregnating sealer. NOTE: Stone Tile Selection and calcareous stones. to stone has oxidized. Photo 83 curb. Removal of stain is not always successful or Installation Guide, "Iron permanent! Staining"

Carefully cut out the cracked grout and apply a Gaps around tubs or The grout is not adhering to flexible, non-shrinking sealant. (100% RTV Showers other dissimilar All Natural stones TCNA EJ171 Photo 77 the dissimilar material. Silicone) In wet areas make sure the substrate is materials. fully dry before applying sealant.

Growth occurring on BOG (Bio-Organic-Growth) is Showers All Natural stones Upgrade to frameless shower door. Photo 67 shower curb. present on shower curb.

© 2016 Marble Institute of America Page 21-101 TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference No permanent solution exists. Temporary Saturated subsurface correction may be achieved by diamond grinding allowing hard water to wick the hard water deposits and removing the grout Photo 33, Showers Hard Water Deposits All Natural stones to stone surface, depositing TCNA F103 and allow to air dry. Regrout when dry. An Photo 112 hard water deposits on stone alternate solution is to apply urethane caulk in surface. place of grout.

There are multiple possible Try the weep holes first. If you cannot get it from causes for this: The weep the inside of the drain then remove the tiles and holes could be clogged; the mud 4-6 inch around the drain and clean the Photo 20, Heavy Water Deposits dry pack may be too tight weep holes from the outside and then set your Photo 21, Showers on Grout Lines in All Natural stones and not allowing the water dry pack again and tile and grout. If the pack is Photo 58, Shower Floor to drain down into the weep too tight, then the entire shower pan tile and Photo 65, holes; or the water proofing mud must be removed and redone. If it is the Photo 66 membrane is not correctly water proofing membrane, well then you must sloped. remove the shower and start over.

Clean with a safe mildew cleaner that will not Inadequate sealing of high etch stone, remove the affected grout lines, use porosity stone, inappropriate Mildew Growth in a dehumidifier to dry out the substrate, when High Porosity stone selection, or high Showers shower walls and grout dry, re-grout, apply the sealer correctly and Photo 122 Stones humidity is maintained in joints inform the client to keep the shower door open area when shower is not in after use. Check the inside grout lines of the use. shower curb also. Clean with the proper mildew remover for Orange, Yellow, or This is frequently the growth natural stone. Bleach only puts the mold in Photo 117, Showers Black Stains in a Wet All Natural stones of mildew as the result of dormancy; it does not kill it forever. Refinishing Photo 122, Area inadequate ventilation the stone may be necessary in some cases (see Photo 123 diamond grinding). Test section with rust removing poultice. Ferrous content indigenous Repolish surface as necessary. Seal stone with Rust bleeding through Light colored to stone has oxidized, and is Showers appropriate impregnating sealer. NOTE: Photo 81 veins in stone calcareous stones traveling through veins as Removal of stain is not always successful or the path of least resistance. permanent!

© 2016 Marble Institute of America Page 21-102 TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference Corrosion protection on shower drain has been Test section with rust removing poultice. Seal Rusting at Shower Showers All Natural stones breached, allowing rust to stone with appropriate impregnating sealer. Photo 83 Drain bleed into surrounding Replace drain. stone. Test section with rust removing poultice. Current TCNA Repolish surface as necessary. Seal stone with Handbook, Natural Photo 89, Rusting on Walls, Light colored Ferrous content indigenous Showers appropriate impregnating sealer. NOTE: Stone Tile Selection and Photo 91, benches, or floors calcareous stones to stone has oxidized. Removal of stain is not always successful or Installation Guide, "Iron Photo 92 permanent! Staining"

Clean out the inside of the drain and then clear the weep holes of white bar soap residue, hair, This is frequently caused by hair conditioner, hard water buildup, and body Shower floor and walls Showers All Natural stones clogged weep holes in the oils. This is for cast Iron drains. Check to verify Photo 62 are darkening drain. that the weep holes are not plugged. Cut around the tar or membrane if necessary so the weep holes are clear.

Surface spalling, usually due to expansion of some Grind and fill as necessary. Encapsulate Photo 82, Showers Spalling of Stone Limestone mineral content during limestone with penetrating epoxy. Photo 97 saturated state. Moisture Resistant Gypsum Board, a.k.a. Tiles becoming Improper substrate typically "Greenboard" is not an appropriate substrate for Current TCNA and MIA Showers dislodged from wall All Natural stones Photo 32 "greenboard" gypsum board. direct application of tiles in wet areas. Remove documents surface and replace. Take out the shower door and cut the grout line on the shower curb on both sides and now into Most commonly, this is the pan. Replace with epoxy grout or a Water penetrating leaking at the shower curb polyurethane sealant. Another option is to tear it Photo 5, Showers All Natural stones sheetrock backing due to inadequate out and start over but slope the shower curb Photo 25 membrane overlap. membrane back to the shower at a rate of ¼ inch per ft. Dry the substrate toughly before re- grouting.

© 2016 Marble Institute of America Page 21-103 TROUBLESHOOTING

Prevention or Photo Application Symptom Stone Type Possible Causes Potential Solutions Cross Reference Reference Removal and replacement per MIA guidelines is White area or surface Certain green Many green marbles and best permanent solution. Use proper setting Showers degradation in green marble and serpentine do not perform materials recommended for serpentine and Photo 49 marble serpentine. well in wet environments. green marble. Use of an impregnating sealer is also helpful.

This is caused by water White Spots on Mosaic Check weep holes, density of dry-pack, and slope Showers All Natural stones evaporation when the Photo 109 Tiles of membrane. shower is holding water.

DSDM, VERTICAL SURFACES – RELATED One stone unit face is proud Either remove the stone and re-set in place with COMPONENTS Section of adjacent units (Note: correct alignment, or diamond grind the proud 2.6 Lippage Photo 90, Walls Lippage on Walls All Natural stones 1/32", or 0.8 mm is stone to match the elevation of the surrounding Photo 93, maximum acceptable stones and refinish to achieve desired level of Current TCNA Photo 94 tolerance). gloss. Handbook, Natural Stone Installations, "Lippage"

Mechanically remove as much residue as possible with a dry brush. Then clean the area Moisture migrating from sub with a mild acid for slate, sandstone, and TCNA F122 Stone White Residue layers carrying salts, which Photo 57, Walls All Stone Types granite. For marble, a slightly alkaline chemical (Concrete) or F101 (Efflorescence) are then deposited on stone Photo 69 can be used. (8-9 on the pH scale). Note: Don’t Stone surface. let it run down a vertical area as it may etch. Some neutral cleaners may also work.

© 2016 Marble Institute of America Page 21-104 Photo # 1 Photo # 2 Spot bonding - improper coverage Bonded to flashing - not suitable bonding substrate

Photo # 3 Photo # 4 Etch ring (resin enhancer disturbed) - correct: use final Resin enhanced slab faded by UV exposure - correct: granite buff pad or powder refinish; use a UV resistant enhancer/colorant

Photo # 5 Photo # 6 Shower curb floor corner waterproof membrane improperly sloped to drain - Improper bonding coverage & improper bonding cracked grout on shower curb (mineral deposits) - correct: remove grout, dry substrate with dehumidifier and regrout with epoxy substrate (flashing)

Photo # 7 Photo # 8 Sandstone improperly sealed (oil stain) - correct: remove stain and Improperly sealed granite (oil stain) - correct: remove seal with multiple applications of appropriate sealer stain with poultice and use multiple applications of sealer

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 1 of 16 © 2016 Marble Institute of America Photo # 9 Photo # 10 Improper bonding, hollow slate tiles - correct: apply scratch to backs of Indent fractures - substrate (rubber soundproof material) slate & use a proper notched trowel method (per TCNA guidelines) - stone cannot take deflection

Photo # 11 Photo # 12 Indent fractures, different cause - builder did not wait 28 Improper edging technique - correct: redo the edge days for thinset to cure correctly

Photo # 13 Photo # 14 Another view of Photo 12 Edge not polished to match factory finish

Photo # 15 Photo # 16 Pits/holes in stone - correct: clean, prep and fill with the Damage from heat - correct: clean soot and smoke with correct patching material degreaser. Will need refinishing if etched.

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 2 of 16 © 2016 Marble Institute of America Photo # 17 Photo # 18 Countertop edge not polished to factory finish - correct: break the Copper stain (caused by copper gutters) - Correct: use mild acid, then seam, relevel the tops with proper support and polish the edges neutralize the acid or use a copper poultice & refinish area

Photo # 19 Photo # 20 Chipped outcorner - correct: replace with matching material or clean, Shower pan holding water and corner improperly sloped to drain - correct: prep and fill with a slow-curing epoxy (not polyester) remove grout & drain and clean the weep holes. Dry thoroughly, regrout and seal

Photo # 21 Photo # 22 Calcium deposit on granite - correct: remove deposit with a straight-edge razor Improper slope to drain, lacking two-stage drain function balde and soapy water (acid can damage plumbing fixture)

Photo # 23 Photo # 24 Structural crack (foundation crack) - correct: replace Different expansion and contraction rates between floor and wall - broken tile correct: use the correct flexible material for this application

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 3 of 16 © 2016 Marble Institute of America Photo # 25 Photo # 26 Waterproofing membrane on the shower curb is not properly sloped to Cracked grout between tile and concrete - correct: install the drain - correct: redo per TCNA guidelines proper expansion joint material (no latex caulk)

Photo # 27 Photo # 28 Crack (at tape) due to improperbond or excessive Copper stain on natural stone - Correct: use mild acid, then neutralize deflection. Also etched. Correct: check floor rigidity, the acid or use a copper poultice & refinish the area

Photo # 29 Photo # 30 Blown rod from using metal in wet area and not Blown rod from using metal in wet area and not encapsulated properly (fiberglass preferred) encapsulated properly (fiberglass preferred)

Photo # 31 Photo # 32 Structural crack (foundation crack) - floor joists too far apart and cannot properly support the weight (live-load and dead-load specification - see TCNA Water intrusion - improper substrate guidelines)

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 4 of 16 © 2016 Marble Institute of America Photo # 33 Photo # 34 Water intrusion into the substrate and permanently Moisture in granite floor - partially hollow - caused by stripping wax & voids in substrate - correct: replace with proper TCNA methods or remove the grout, staining the tile on the way out thoroughly dry and regrout (inject with adhesives to fill voids before grouting)

Photo # 35 Photo # 36 Pitting in granite from high mica content in the stone - Pitting similar to that shown in Photo 35 correct: clean, prep and fill with epoxy or CA glue

Photo # 37 Photo # 38 Poor quality stone (close up) - correct: replace the Poor quality stone (different view) - correct: replace the countertop countertop

Photo # 39 Photo # 40 Poor quality installation methods and lack of bonding material - correct: clean Swirl marks - correct: Start refinishing from the least abrasive diamond grit until the back of tile and substrate and reinstall using proper TCNA installation the swirl marks are removed. Proceed to finer grits until the desired gloss level is methods achieved.

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 5 of 16 © 2016 Marble Institute of America Photo # 41 Photo # 42 Oil staining in granite countertop - correct: use oil poultice and Tape residue - correct: use acetone and a white pad - if the seal thoroughly with multiple applications stone is stained below, then refinishing may be needed

Photo # 43 Photo # 44 Natural seams in the stone that have fully opened to be Soap residue or surfactants from using the wrong cleaners - correct: remove repaired like a crack or fracture with warm water and a good rinseless cleaner and a white pad

Photo # 45 Photo # 46 Etch marks on polished travertine - correct: refinish the Iron stain in white marble (white stones have iron content which oxidizes with stone back to the factory polish moisture over time) - correct: use a rust poultice and refinish the stone

Photo # 47 Photo # 48 Natural voids in some limestone - correct: clean, prep and Shower pan holding water - correct: remove grout in critical fill with epoxy areas, clean weep holes, thoroughly dry, grout and seal

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 6 of 16 © 2016 Marble Institute of America Photo # 49 Photo # 50 Lack of slope, moisture evaporation causing spalling - Pressure on edges causing cleavage in stone to break off - partially hollow tile at the edge - correct: wet or dry sand the slate until smoother and fill void in with correct: remove and replace using TCNA guidelines adhesive, then regrout

Photo # 51 Photo # 52 Tape stain - oils from adhesive staining the stone - correct: vigorously clean with Badly etched stone shower - correct: grinding, refinishing acetone and a white pad, grinding and refinishing may be necessary and seal

Photo # 53 Photo # 54 Substructural crack on wall - correct: replace tile or clean, prep and Multiple coats of topical sealer on a textured granite floor - correct: carefully repair tile and refinish as necessary to smooth out repair strip the floor, allow to thoroughly dry and use an impregnator

Photo # 55 Photo # 56 Another view of too many coats of topical sealer on a Another view of too many coats of topical sealer on a textured granite floor textured granite floor

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 7 of 16 © 2016 Marble Institute of America Photo # 57 Photo # 58 Hollow installation, efflorescence from joint resulting Shower pan holding water and wicked off the walls past from moisture trying to escape the membrane

Photo # 59 Photo # 60 Blown rod from using metal in wet area and not Holes in travertine - correct: clean, prep and fill with epoxy encapsulated properly

Photo # 61 Photo # 62 Inadequate waterproofing membrane installation leading to potentially clogged Using an enhancer on a moist floor - correct: strip the old enhancer, allow the weepholes - correct: redo the the process according to TCNA guidelines and floor to thoroughly dry and reapply enhancer correctly plumbing code

Photo # 63 Photo # 64 Granite countertop edge not properly polished to match factory finish - Improper specification of material - very porous material in a wet area - correct: correct: repolish the edge correctly multiple sealing applications on multiple days

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 8 of 16 © 2016 Marble Institute of America Photo # 65 Photo # 66 Shower pan with clogged weepholes - correct: carefully remove grout, clear out the weepholes and allow substrate to thoroughly dry, then regrout and seal Inside of drain in MIA Photo 65

Photo # 67 Photo # 68 Lack of slope on shower curb Spalling - correct: replace or clean, prep and repair

Photo # 69 Photo # 70 Efflorescence - face of a waterfall in a pool - correct: use Grout cracked - correct: cut out the grout and install an a mild acidic cleaner and neutralize expansion joint material (driveway)

Photo # 71 Photo # 72 Possible spacer used when resining stone slab leaving a stain within the Holes in a travertine - correct: clean, prep and refill resin - correct: completely refinish or replace

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 9 of 16 © 2016 Marble Institute of America Photo # 73 Photo # 74 Lippage - Maximum accepted lippage for the stone industry - correct: Sealer streaking - correct: break down the sealer and follow replace or grind and refinish back to specs manufacturer's recommendations

Photo # 75 Photo # 76 Hollow edge - correct: replace tile or repair using the proper amount Blown rod from using metal in wet area and not setting material to support the hollow areas, then clean, prep and fill encapsulated properly (fiberglass preferred)

Photo # 77 Photo # 78 Different expansion and contraction rates between rigid and flexible Excess sealer materials - correct: use the correct flexible material for this application

Photo # 79 Photo # 80 Chip - correct: clean, prep and fill with epoxy or CA glue Spalling - correct: replace

Restoration & Maintenance SITE PHOTOGRAPHS Troubleshooting Page 10 of 16 © 2016 Marble Institute of America Photo # 81 Photo # 82 Iron oxidation - use a rust poultice, then seal thoroughly spalling on limestone shower floor - correct: replace floor

Photo # 83 Photo # 84 Rust stain on limestone shower floor - rusted drain Spalling - correct: replace stone

Photo # 85 Photo # 86 Dyed stone Dyed stone - another view

Photo # 87 Photo # 88 Indent fracture - lack of bonding adhesive in the corner - Shrinkage cracks - too much thinset adhesive used - correct: replace tile correct: replace

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 11 of 16 © 2016 Marble Institute of America Photo # 89 Photo # 90 Same as MIA 91 & 92 - defective material for a wet Excessive lippage - correct: replace the material application - correct: replace the material

Photo # 91 Photo # 92 Same as MIA Photo 89 & 92 - defective material for a wet Same as MIA Photo 89 & 91 - defective material for a wet application - correct: replace the material application - correct: replace the material

Photo # 93 Photo # 94 Misaligned, hollow and incorrectly spaced - correct: Hollow tiles and spalling remove and replace

Photo # 95 Photo # 96 Stone not properly sealed Stone not properly sealed

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 12 of 16 © 2016 Marble Institute of America Photo # 97 Photo # 98 Spalling - moisture intrusion behind the wall - correct: Tenting - remove and replace affected tiles. Add replace it movement and/or expansion joints per industry

Photo # 99 Photo # 100 Blown rod from using metal in wet area and not Oil staining in granite countertop - correct: use oil encapsulated properly (fiberglass preferred) poultice and seal thoroughly with multiple applications

Photo # 101 Photo # 102 Soap staining granite countertop - correct: use towel Oil staining in granite countertop - correct: use oil saturated with mineral spirits. Repeat as necessary. poultice and seal thoroughly with multiple applications

Photo # 103 Photo # 104 Green (environmental) citrus cleaner on a marble floor Efflorescence in slate used to clean the grout - correct: refinish the floor

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 13 of 16 © 2016 Marble Institute of America Photo # 105 Photo # 106 Tile separation due to lack of expansion joint - correct: cut grout Stain from planter - correct: mild acid wash, neutralize, and replace with appropriate expansion joint detail. refinish (blend and feather out)

Photo # 107 Photo # 108 Project in Photo 108 after installation of expansion joints Lack of bonding adhesive under the tile - correct: use and proper bonding correct type and amount of bonding.

Photo # 109 Photo # 110 Ceramic tile - pan is holding water - correct: remove tiles, clear the Etch mark on 'marble' - correct: refinish weepholes and replace per TCNA guidelines

Photo # 111 Photo # 112 Spalling - wrong thinset on a large format tile - latex, modified thinset Hard water deposits on black marble - correct: temporary fix: diamond instead of a medium bed mortar - correct: replace grind, remove & replace grout when dry, or replace stone

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 14 of 16 © 2016 Marble Institute of America Photo # 113 Photo # 114 Another view of Photo 114 Demonstrating surface slope. Ball bearings roll downhill.

Photo # 115 Photo # 116 Moisture in substrate permanently staining slate pavers - Close-up of Photo 115 tile sloped but the membrane is not

Photo # 117 Photo # 118 Fungus - the start of mold in the grout line - correct: use a mildew Sealing in hot dry environment - dries too quickly cleaner that will not damage marble

Photo # 119 Photo # 120 Sealer walk on before dry - correct: re-emulsify sealer and buff. Deck insufficiently sloped away from building - correct: May have to refinish. remove and reinstall properly

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 15 of 16 © 2016 Marble Institute of America Photo # 121 Photo # 122 Cracks caused by material handling, substrate deformation, or Same as MIA Photo 123 - lack of proper maintenance, lack of proper sealing and vibration from field cutting keeping shower door closed after use (not allowing moisture to escape)

Photo # 123 Photo # 124 Same as MIA Photo 122 - lack of proper maintenance, lack of proper sealing and Polishing compound too hot (orange peel) - correct: keeping shower door closed after use (not allowing moisture to escape) refinish with 'cold' powder.

Photo # 125 Photo # 126 Close up of 124: Polishing compound too hot (orange Excessive grout haze - correct: carefully clean excessive grout off of calcium peel) - correct: refinish with 'cold' powder. based stone (if an acid is used, neutralize the acid and refinish the stone)

Photo # 127 Photo # 128 Settling and chipped edges (caused by butt joint installation - Spalling on outside of shower minimum 1/16" gap)

Restoration & Maintenance SAMPLE PHOTOGRAPHS Troubleshooting Page 16 of 16 © 2016 Marble Institute of America

Restoration and Maintenance Additional Learning Resources

Stone Behavior Groups, pp. 21-10–16

 For more information about Crema Marfil and the company and quarries that produce it, see, http://www.levantina.com/us/.  Online Resource: http://www.natural-stone-database.com, type “Crema Europa” in the search box.  Online Resource: http://www.bempe.com/en/crema-europa-limestone  Stone Care Guide, Ted McFadden. 2008.

Restorative Processes, pp. 21-51–66

 Stone Care Guide, Ted McFadden. 2008.  Online Resource, http://www.stonerefinishing.com

Maintenance, pp. 21-75–84

 ASTM C1515–11, Standard Guide for Cleaning of Exterior Dimension Stone, Vertical and Horizontal Surfaces, New or Existing.  Cleaning Masonry – Review of the Literature by Grimm, Clayford T., P.E. Construction Research Center, and University of Texas at Arlington, 1988.  Cleaning Stone and Masonry, Clifton, James R., Editor. ASTM Special Technical Publication 935, American Society for Testing and Materials, 1983.  Keeping It Clean by Grimmer, Anne E. U.S. Department of the Interior, National Park Service, Washington, DC: U.S. Government Printing Office, 1988  “Cleaning of Masonry Interiors of Public Buildings,” Cleaning Stone and Masonry by Roth, J.W., ASTM STP 935, 1986.  “Chemical Cleaning of Historical Structures – A Practical Approach,” Cleaning Stone And Masonry by Rudder, T.H., ASTM STP 935, 1986.  “A Case Study of the Cleaning of Marble at the Schenectady, New York, City Hall,” Cleaning Stone and Masonry, by Waite, J.C. and R.J. Chen, ASTM STP 935, 1986.  “A Macrosteriogrammetric Technique for Measuring Surface Erosion Losses on Stone,” Cleaning Stone and Masonry by Winkler, E.M., ASTM STP 935, 1986.

Commercial and Historic Restoration, pp. 21-85–88

 Occupational Safety and Health Administration (OSHA): https://www.osha.gov/law- regs.html

 2016 Marble Institute of America Additional Learning Resources • Page 21-121  Occupational Safety and Health Administration (O.S.H.A.) – Guide to Controlling Silica Exposure: https://www.osha.gov/Publications/3362silica-exposures.pdf  Union Requirements – National Labor Relations Board: http://www.nlrb.gov/rights-we- protect/employerunion-rights-and-obligations  Federal Labor Requirements – United States Department of Labor: http://www.dol.gov/whd/programs/dbra/wh347.htm  National Park Service – Historic Rehabilitation Guidelines: http://www.nps.gov/tps/standards/rehabilitation/rehabilitation-guidelines.pdf  National Park Service – The Secretary of the Interior’s Standards for Rehabilitation: http://www.nps.gov/tps/standards/rehabilitation/rehab/stand.htm  National Park Service – Tax Incentives: http://www.nps.gov/tps/tax-incentives.htm  National Park Service – Register of Historic Places Database: http://www.nps.gov/history/nr/research/  Milan Restoration Triumph – InfoTile.com http://www.infotile.com/pdfFile/Product/ProductFile/1604201343759.pdf  Historic Preservation – Technical Procedures: http://www.gsa.gov/portal/content/111858  National Trust for Historic Preservation: http://www.preservationnation.org

DSDM 7.2 (2011)

 ASTM International, ASTM C119, Standard Terminology Relating to Dimension Stone. West Conshohocken, PA: ASTM International.

 National Tile Contractors Association, NTCA Reference Manual. 2011. Jackson: NTCA.

 Tile Council of America, Tile Council of North America Installation Handbook. Princeton: TCA, 2011.

 International Code Council, 2012 International Plumbing Code. ICC, 2011.

Page 21-122 • Additional Learning Resources  2016 Marble Institute of America