Polishing Concrete

A Durability + Design Collection Polishing Concrete

A Durability + Design Collection

This eBook may not be copied or redistributed without the written permission of the publisher. SPONSORED BY: ii

Contents

iv. Introduction

Getting Up to Speed on Concrete Polishing 1 by Mark Vogel, W.R. Meadows A Real Grind: Concrete Polishing “101” Offers Multiple Rewards 7 by Gary Henry, Durability + Design Concrete Flooring: Polished or Coated? 9 by Gina R. Johnson, Durability + Design Crunching the Numbers on Polished Concrete, Other Flooring Types 16 by Walter Scarborough, HALL Building Information Group, LLC

Artistry and Chemistry: Color Theory and Practice with Polished Concrete 23 by Howard Jancy, Jancy & Associates

Keeping the Shine: 29 Basic Training in Maintenance of Polished Concrete Floors by Howard Jancy, Jancy & Associates

Defining the Undefinable 34 by Brad Burns, Concrete Polishing Association of America SUPERIOR POLISHING PRODUCTS FROM H&C® DECORATIVE CONCRETE

H&C CLEAR LIQUID HARDENER & DENSIFIER • Densiﬁes and hardens new and existing concrete • Penetrates and reacts with concrete faster than conventional systems • Minimizes labor costs - is easy to apply, polish & maintain

H&C LITHIUM PROTECTIVE FINISH • Protects polished concrete • Increases concrete hardness and improves stain resistance • Provides high gloss reﬂectivity when burnished

ADD COLOR WITH H&C ACETONE DYE STAINS • Available in 16 packaged colors • Colors can be inter-mixed to achieve even more colors • Dry to touch in 20-40 minutes • Perfect for polished concrete or existing substrates

A comprehensiveccomprompprrehenehensivvee lineline for r allall your AvailableAAvvailable at yyourour local decorativedeccororratiaativvee cconcrconcreteoncrretettee nneeds.eeds. Sherwin-WilliamsSherwin-Williams store.store. Scan the code to sign up for our e-newsletter!

For more product information, visitvisit wwww.hcconcrete.comww.hcconcrete.com or call 1-1-800-867-8246800-867-8246 iv

Introduction

This eBook consists of articles from Durability + Design (D+D), durabilityanddesign.com, the Journal of Architectural Coatings (JAC), and Painting and Wallcovering Contractor (PWC) on the subject of polished concrete coatings. More articles on this topic may be found online at durabilityanddesign.com.

Cover image courtesy of Brad Burns, CPAA. See the full article on page 33. (Right) Photo courtesy of H&C Decorative Concrete Products 1

By Mark Vogel, W.R. Meadows

Editor’s Note: This article appeared in JAC in December 2008.

Enhanced performance and appearance attributes have contributed to the increased use of polished concrete in a variety of public and institutional settings. This article reviews the concrete polishing Getting Up To Speed on process, including grinding, surface Concrete Polishing preparation, densifier Grinding, densification systems get sustainability points for buffed-up application and floor performance and appearance attributes polishing.

he range of flooring options available in today’s marketplace is vast, with each of these T alternatives offering unique appearance and performance characteristics. As a result, owners and design professionals must evaluate many factors to determine the best flooring option for a structure’s given needs and environment. 2

One flooring system or option currently gain- lows transmission of water vapor and thus is ing in popularity is polished concrete. Al- not subject to failure due to moisture migration though polished concrete is relatively new in from below. North America (approximately 15 years), the When properly installed and maintained, system offers many advantages. polished concrete can last the life of the struc- Concrete is a durable material, and thus ture, avoiding the time and labor of installing meets an important sustainable-design crite- subsequent flooring systems. rion. In addition, the polishing process en- Polished concrete can be used in almost any hances concrete’s natural appeal. These interior area. In exterior settings, however, acid attributes have contributed to the increased use rain has a tendency to prematurely etch the sur- of polished concrete in public and institutional face and cause early deterioration of the shine. buildings such as schools, hospitals, retail Polished concrete can be treated with integral stores, restaurants and other settings. concrete colors, color dyes, and edge-tinting In this discussion, we will seek to provide a products to produce an attractive floor surface. review of the polished-concrete process, which Maintenance is relatively simple and eco- involves a sequence of steps that begins with nomical, and involves cleaning the surface with initial grinding and preparation of the floor. an agent formulated for this purpose. A con- Application of densifying agents and polishing centrated cleaning solution with a neutral pH is with machines employing diamond-grit discs added to the cleaning water in an auto scrub- produce a surface that is durable, attractive, ber. The auto scrubber applies the cleaning so- and highly reflective. A major factor in the in- lution, buffs, and vacuums any remaining Polished concrete can be used tegrity and performance of polished concrete is solution and dirt particles, leaving no residue in almost any interior area, and the use of high-quality liquid hardener and can be treated with integral and a clean surface. Maintenance of polished concrete colors, color dyes, and densifier materials. concrete is quite low in cost, averaging 5 to 7 edge-tinting products to cents per square foot per year. No special produce an attractive floor Polished concrete: An overview waxes or strippers are required. surface. Photos courtesy of Polished concrete, because it does not involve W.R. Meadows Inc. a coating, is a breathable system—one that al- Dry or wet process With dry polished concrete, vacuums are used to extract dust; with wet polished concrete, wet slurry is used to remove concrete particles. The wet-grinding process requires special disposal methods. With dry polished concrete, pre-separators and vacuum systems are used to control air- borne dust and contaminants. The dry powder or cement particles can be safely disposed of and can even be recycled. Incorporating a low- or zero-VOC (volatile organic compound) hardener/ densifier completes a “green,” en- vironmentally friendly flooring system. A densifier works by chemically converting weak calcium hydroxide [Ca(OH)2] and calcium carbonate (CaCo3) compounds in the 3

Attaining the desired level of shine in polished-concrete installations depends on the number of passes of the diamond disc grinder, as each step increasingly flattens the floor and enhances light reflectivity.

concrete to form calcium silicate hydrate vided into two categories: Those employing (CSH). CSH is insoluble in water and is highly metal-bonded diamonds (16 to 150 grit) that resistant to water, acids, and other chemicals. are used in the initial grinding or preparation The formation of the CSH is proportionate to phase, and resin-bonded diamond segments increased concrete hardness and density due (100 to 3000 grit) that are used in the subse- to the replacement of soluble lime [CA(OH)2] quent polishing phases. Metal-bonded dia- with CSH. Once the concrete pores are filled monds are more aggressive in their effect on with CSH, migration of moisture from the sur- the concrete substrate than resin-bonded dia- face to the substrate will be inhibited, as the mond segments. process produces a hard, dense, and sealed The initial grinding step removes high spots, surface in which abrasion resistance is in- imperfections, and contaminants such as cure creased by approximately 50%. and seal materials, mastics, or chemicals. This Concrete densifiers are typically based on grinding phase may require one to three lithium silicate, sodium silicate, and potassium stages, but it will consume 60-65% of the total silicate. time required to complete the densification/polishing process. Grinding and The process steps prep work are critical, however, in achieving A true grinding and polishing system requires the ultimate result in the final floor finish. a process consisting of five to 10 steps, de- Resin-bonded diamonds are used following pending on the desired shine of the floor and application of the hardener/densifier to polish its original condition. Assessing the condition and remove the scratch pattern created by the of the concrete requires on-site analysis, gen- initial grinding process. eral knowledge of concrete and mix design, The three primary degrees of shine are cat- and diagnosis of hardness, porosity, and ag- egorized based on the diamond grit of the gregate types. final polishing step: 800, 1500, or 3000— Grinding and polishing techniques are di- which translate to semigloss, gloss, and high- 4 gloss finishes. The cost increases incrementally of the remaining material from the surface, de- by 10–15% when upgrading from a semigloss pending on heat and airflow conditions. Spe- to a gloss range, and another 8–12% when cific manufacturer directions should be upgrading from a gloss to high-gloss range, referenced, as some application methods vary. based on the total value of the project. The ma- It is critical to not allow the densifier to dry jority of the cost is related to the preliminary on the surface, as this may leave a white preparation stages, as labor intensity is great- residue or haze. Large quantities or concen- est in the grinding stages. trations of densifier left on the surface are dif- A mock-up at the job site is always the best ficult to remove and may actually stain the way to identify the capabilities of the desig- concrete a dark color. Water is used to help re- nated slab and its affinity to the polishing move any remaining densifier. process. In addition, the mock-up can help de- The recommended temperature and humid- termine the polishing level needed to suit the ity ranges for densifier application vary from building and achieve satisfaction of the cus- manufacturer to manufacturer; product guide- tomer and its occupants. lines should be referenced. The installer can A final, optional step involves application of extend the application time by adding more a type of topical or penetrating agent to im- densifier in the first 15 to 20 minutes, as the mediately seal the surface until the densifier concrete can readily absorb the additional ma- can fully develop to its potential. Because the terial. Water can be added after 20 minutes, densifier must fill all the voids in the concrete as this will thin the densifier material as it gels through a chemical reaction, sealing does not to help facilitate deeper penetration and sim- happen immediately and is highly dependent plify the job of removing excess product. on the porosity of the concrete. The environmental profile of the densifier product also plays a primary role in the Densifying and hardening “green” credentials of the specific concrete- Once the metal-bonded diamond phase and polishing process. This profile is determined by prep is complete, the densification process be- VOC content, the nature of the waste material gins. This key step plays a central part in generated, and disposal parameters. achieving longevity of the shine and a high The entire densification process takes ap- level of performance of the finished floor. Den- proximately 30 to 45 minutes. The surface is sification results in a water-, stain-, and chem- then allowed to dry for 24 hours before the ical-resistant surface. resin-bond diamond segments are used to pol- After the initial grinding stage “opens” the ish to the desired level. The process produces a concrete to facilitate the chemical reaction of hard, dense, and sealed surface. the densifier and concrete, a sprayer or squeegee is used to apply the liquid densifier Adding color at a rate of 16 to 19 square meters per liter If coloring of the concrete is part of the pic- (175 to 200 square feet per gallon). The den- ture, numerous options are available, includ- sifier is allowed to soak in for 10 minutes, and ing integral coloring of the concrete, staining, is then scrubbed into the surface for 15 to 20 and dyeing. minutes (or until gel formation) with a broom With integral coloring, an admixture is in- or, preferably, an auto scrubber for optimum corporated in the concrete mix to produce uni- penetration. This is followed by a light misting form color throughout the slab. With a dye or of water, and then a re-scrubbing and flushing stain, the concrete surface is colored before 5 applying the densifier, allowing unlimited color the range of 45 to 65) exceeds OSHA (Oc- combinations and edge-tint options. Dyes or cupational Safety and Health Administration) stains are typically applied after polishing at and Americans with Disabilities Act (ADA) the 400-grit level. A second coat may be standards for coefficient of friction and slip added later in the process or at the end to in- resistance, which are the two most widely ac- crease the effect or intensity of the color. Care cepted standards for these safety criteria. The should be taken to wash the surface of dyed process creates an attractive environment or stained sections with water, followed by with increased light reflectivity, a desirable complete drying before the next polishing characteristic in today’s safety-conscious phase begins. marketplace. Standard coefficient of friction (COF) num- Levels of shine bers for an 800-grit or semigloss polished-con- Attaining the desired level of shine depends on crete surface will range from .79 to .84, a the number of passes of the diamond disc 1500-grit or gloss finish will yield a COF of grinder, as each step increasingly flattens the .84 to .87, and a 3000-grit or high-gloss fin- floor and enhances light reflectivity. Polishing ish will yield a COF of .87 to .89. These num- systems that require minimal process steps— bers all exceed the OSHA standard of .50 and less than five—do not constitute a true grinding the ADA standard of .60 on flat surfaces. The and polishing system, which involves a five- to flatter the floor, the higher the standard of co- ten-step process, including the hardening and efficient of friction. densification application. These less-complete (and lower-cost) types of Polished concrete: An effective systems are commonly referred to as topical, as solution on several counts their penetration of the surface is limited, leading With the vast amount of flooring options avail- to early wear and loss of gloss and reflectivity. able today, architects, specifiers, and owners are well advised to consider all available op- The safety issue: Polishing and slip tions to meet the needs of a structure and its Contrary to a common perception, the degree occupants. Issues such as durability, safety, ini- of polish or shine is not directly related to slip tial and ongoing maintenance costs, replace- resistance. A 400-grit finish can and usually is ment needs, the service environment, and the less slip-resistant than a 1500- or 3000-grit environmental profile of the system should be final finish. weighed in determining the ideal flooring sys- It helps to think of it in this way: when a floor tem for the given setting. Polished concrete can is wet and a person walks on it, the peaks and provide an answer to many of these needs by valleys in the landscape of the surface create a enhancing a common building component— tendency for the person to “hydroplane.” On a concrete—that meets the definition of a sus- completely flat surface such as that produced tainable building material in many ways. by 1500 or 3000 grit, the water is pressed out In evaluating any flooring option, it is impor- from under the shoe, putting the sole directly in tant that best practices and detailed specifica- contact with the concrete surface—actually tions are employed. Effective choices regarding making the shoe stick to the surface. flooring systems can deliver safe, environmen- A true grinding and polishing system with tally friendly solutions that are cost effective and the highest levels of shine (using 3000-grit contribute to the highly coveted goal of sus- polishing) and gloss (gloss meter readings in tainability in design and construction. D+D 6

Polishing revs up the performance of concrete floor at racecar art shop

They may be making a extended pit stop for cosmetic alterations, but the sleek racing cars at JKS Motorsports in the heart of North Carolina’s NASCAR country almost appear to float on the shim- mering polished-concrete floor at the company’s new facility in Welcome, NC. JKS Motorsports, which creates logos and other artistry that decorates stock- car racing vehicles, placed a bet on polished concrete as a practical, but eye-appealing, surface for the company’s new facility. The process trans- formed 34,000 square feet of plain gray concrete into a glistening, reflective surface courtesy of the INDUROSHINE system developed by W.R. Meadows Inc. The facility was a design/build project by Samet Corp., Greensboro, NC. The are changing the composition of the con- ment that enhances reflectivity and re- concrete contractor was Triad Construc- crete, and it’s a permanent solution.” sistance to staining from oil, grease, and tion Services, High Point, NC. The con- The project began with initial grinding other petroleum-based substances. crete polishing contractor was Blair to prepare the surface for application of The owner opted to retain the inherent Duron, Raleigh, NC. the liquid sodium silicate densifier, with gray color of the concrete rather than in- Casey Chandler, W.R. Meadows’ 45-, 80-, and 150-grit discs used. W.R. troduce color by means of integral color- sales representative in the Carolinas Meadows’ Liqui-Hard densifier was spray ing of the concrete or field application of and Virginia, gives high marks to Triad applied, then left in place for a dwell time stains or dyes. A 10-inch-wide strip of for installation of a high-quality, hard- of 45 minutes to an hour. Any excess solid-color epoxy coating was applied, troweled, water-cured, 3,500-psi con- densifier remaining on the surface was crete mix design, providing a sound however, to floor edges along walls that then removed with water and shop vac- basis on which to work some polished- were not given the polishing treatment. A uum. The next day, the polishing was concrete magic. separate edge treatment of this type is completed with increasingly finer dia- often recommended due to the logistical Chandler says he was able to make a mond grits of 110, 400, and 1,500 sizes. limitations of the grinding and polishing case for the polishing process, based on In some projects, the polishing stage equipment. The burgundy-colored coat- attributes that include light reflectivity, can progress all the way to a 3,000-grit ing provides contrast—an accent to the durability, slip resistance (impression of stage, but the hard-troweled concrete in natural color of the concrete surface. slickness to the contrary), and resistance this case didn’t require the finer-grit pol- The resulting mirror-like, polished sur- to abrasion, oil, and chemicals. A key ishing, Chandler says. face stands in marked contrast to the selling point was the relative permanence Chandler concedes that the tech- slate gray of a conventional concrete of the densified and polished concrete. niques are “something like an art. You The polishing process is without a doubt have to evaluate the conditions and op- floor. For JKS Motorsports, it has the labor intensive, but should not have to be erate sophisticated machinery.” look of a winning entry. repeated if successfully executed. A final step was applying W.R. Mead- Gentlemen, start your polishing-ma- “With polished concrete, it’s essentially ows’ Bellatrix, a propriety topical treat- chine engines! a one-shot deal,” Chandler says. “You —Joe Maty, J. Maty Communications 7

By Gary Henry, Durability + Design

Editor’s Note: This article was published online in May 2011.

Participants in the Concrete Polishing Association of America’s Craftsman Accreditation Course begin grinding the mezzanine-level floor at “Rocketown,” a non-profit youth facility in Nashville, Tenn. Photo courtesy Concrete Polishing Association of America

A REAL GRIND: Concrete Polishing “101” Offers Multiple Rewards

ust a few blocks from the Country Music taught the back-to-back two-day courses. Reps from Hall of Fame, Nashville’s non-profit “Rock- CPAA member companies supported the training J etown” offers young people a drug- and al- with donated equipment and supplies, including cohol-free venue that includes a concert hall, indoor PROSOCO’s Joe Reardon and 25 gallons of the skateboard park, and some really old concrete floors. company’s Consolideck® LS® (Lithium-Silicate) The facility got “pro bono” help with the floors Hardener/Densifier. March 2011, as two Craftsman-level accreditation Along with Rocketown’s aged concrete floors, two courses taught by the Concrete Polishing Associa- classes of concrete professionals—mostly flatwork tion of America (CPAA) swept through, in conjunc- and polishing contractors, Brad said—were the tion with the Concrete Décor Show. beneficiaries of the training. Aside from hours of CPAA instructors Brad Burns, First American hands-on training on real-world floors, participants Floor Co., Grapevine, Texas; Roy Bowman and got classroom training in “The Polishing Process,” George Gooch, Concrete Visions Inc., Tulsa, Okla.; “The Science of Polished Concrete,” “Estimating Pol- and Derek Mackenzie, Floor Lab, Toronto, Calif., ished Concrete,” and more. 8

(top) George Gooch, left, and Derek Mackenzie spray and spread Consolideck® LS® on a concrete floor in Rocketown. Photo courtesy of Joe Reardon (above) The Coffee Bar floor at Rocketown gleams after treatment with a lithium-silicate hardener/densifier, grouting system and polishing to a 1500-resin finish. Photo courtesy Concrete Polishing Association of America

Rescuing ‘Abused’ Coffee-Bar Floor tremely hard to advance the education, benefits and The Monday-Tuesday class took on the abused and aesthetics of polished concrete,” Brad said. deteriorating 2,500-square-foot concrete floor in The CPAA courses were part of a “decorative Rocketown’s first-floor coffee bar. concrete makeover” for the Rocketown youth cen- Pre-repair work to the floor included treatment ter, carried out in conjunction with the Concrete with the lithium-silicate hardener densifier, follow- Décor Show. The project was the subject of a Dura- ing grinding with 80-grit metals. Husqvarna bility + Design story, Opening-Act Preview: Con- GM300 grout went down to further improve the crete Décor Makeover to Transform‘Rocketown.’ surface for polishing after grinding with 150-grit For more information about the Concrete Polish- metals. The two treatments did the trick, and the for- ing Association’s schedule of classes and registra- merly soft surface ended with a hard, shiny 1500 tion procedure, visit the Education page on the resin finish. group’s website. The Wednesday-Thursday class faced its own chal- Gary Henry ([email protected]) lenge, Brad said. Participants had to lift some heavy- is Durability + Design's managing editor. D+D duty machines—the STI Prepmaster 2417 and the HTC 650HDX—with a Skytrack crane to the second- floor mezzanine overlooking the skateboard area.

Mezzanine Floor Less Daunting The 1,000 square feet of mezzanine concrete was in much better shape than the coffee bar, Brad said. Other than location and a thin gray surface coating that ground off easily, the floor presented no obstacles. Along with the class participants, Brad said, the crew at Rocketown and the Concrete Decor Show were great to work with and helped tremendously. “Everyone put in long hours and worked ex- 9

By Gina R. Johnson, Durability + Design

Editor’s Note: This article appeared D+D in November 2013.

CONCRETE FLOORING: Polished or Coated? Experts go head to head, describing where each treatment shines

wo formidable flooring options, each with its own applications and strengths. But which T one, polished or coated concrete, is best for your particular situation, and what can you expect in terms of maintenance, durability and aesthetic options? 10

We invited two long-time practitioners to discuss the differences, along with innovations and challenges of the trade. Jim Cuviello has been in the concrete polishing industry since 2002. He owns Cuviello Concrete in Stevensville, Md., and is a founding member of the Concrete Polishing Associ- ation of America (CPAA). Phil Scisciani founded Specialty Coatings & Consulting Inc., in Pittsburgh, in 1990. Along with KTA-Tator’s Kevin J. Brown (see “Polished Need Not Mean Slippery,” page 26), they participated in a Durability + Design panel discussion in January. (View it at durabilityanddesign.com/videos.) We picked up the conversation this fall.

D+D: How do you help an architect, specifier or building owner understand the options? CUVIELLO: We do a lot of AIA presentations, so we start setting the expectations right there to let them know of what they can expect polished concrete will and will not do. Particularly if it’s an existing facility, if there’s damage to the floor, we always tell them a patch is a patch, don’t expect anything different. If there’s existing tile or glue on the floor, we let them know that when that stuff is removed and the surface is polished, any imperfections underneath or any lines created by tile patterns are going to stay there. If it’s a new pour, we let them know that concrete has imperfections, that they should expect that the surface when finished is going to be consistently inconsistent. And again, if they’re looking for something perfect, they should go buy something that’s manufactured (top) Polished concrete is ideal in retail areas, school corridors, car dealerships, offices, warehouses and certain areas of grocery stores. in a factory with tight quality controls. Photo courtesy of Cuviello Concrete. SCISCIANI: Jim, how much problem do you (middle) In settings where liquids, oils or acidic materials are common, like run into explaining to people about polished at this service bay at a Pennsylvania Honda dealership, experts concrete? You know, how everyone wants to recommend a coated concrete floor. Photo courtesy of garagecoatings.com. (above) This large commercial laundromat in New York was an ideal see [exposed] aggregate look vs. the cement candidate for a coated concrete floor. It uses an epoxy coating with to cream. decorative flake broadcast into it under a polyurea topcoat. Photo CUVIELLO: We let everybody know that courtesy of garagecoatings.com. 11

there’s three degrees of cut. There’s working evaluating what’s the best solution. If it’s newer with the cement paste, which is the concrete concrete, then you go with a thinner system. cream. We can remove the concrete cream and So it’s really [about] the conditions of the con- expose the fine aggregate, the sand aggregate, crete and what they’re using it for. or we can go further down into it and expose CUVIELLO: You know, our primary [focus] the coarse aggregate in addition to the sand for the next year is schools. And I couldn’t aggregate in between the coarse aggregate. imagine a school with epoxy throughout all of But when we talk about setting expectations, the corridors and all of the classrooms. I mean, flatness numbers are so important. Because if I know that there are aesthetically pleasing we have a low floor flatness, let’s say it’s a 20 epoxy systems. I don’t personally see that as a or 25, the machines, as they travel across the good fit, whereas I think polished concrete is a surface, unless we set the heads up to be ex- more decorative application, and that’s a bet- tremely flexible, they will end up with incon- ter fit for like a school system in corridors and sistent degrees of cut. The low spots may be in some classrooms. Obviously in laboratories, cream, the high spots may actually be coarse they might want to go epoxy. aggregate; you may have the sand aggregate SCISCIANI: I agree with you 100 percent in between. that polished concrete in school hallways and If it’s on existing concrete, the challenge is if classrooms are a good fit. But I think when you somebody was walking on the concrete and get into locker rooms, restrooms and kitchen they pushed the aggregate down, when we floors, a decorative polymer floor coating is a grind, we may not be able to reach the ag- good alternative. Old school is to install vinyl gregate where it was pushed down. So these tile, ceramic or quarry tile in these areas. Dec- are things that we have to let them know are orative colored-flake system, which can even possible. create a terrazzo appearance, is a good al- What often is painful for them to hear is ternative. So I think that’s a prime example of they’re paying for the process, not the out- where polished concrete and polymer systems come. We’ll perform the process in the best will go hand in hand pretty well. possible manner to deliver the best possible re- CUVIELLO: I agree. Anytime we see any- sults, but you know, these are things that are body specifying polished concrete in a locker (top) Cuviello notes that it’s beyond our control and can come up. Now, if room or restroom or kitchen or food setting, I important to set client expec- it’s a new concrete pour, we can head a lot of always recommend a seamless epoxy system tations about flatness. A low that stuff off and make sure that the finishers that wraps up on the wall, [for] ease of main- floor flatness can result in finish the concrete in a way that doesn’t create tenance. You know, polished concrete in the uneven degrees of cut, as shown here. these problems. [We can] even seed additional bathroom is a nightmare. (middle and above) As this aggregate into the surface to make sure that New York project demon- it’s consistent. D+D: What are some common installation strates, polishing can’t hide SCISCIANI: As far as [setting client expec- issues? cracks, patches and different concrete pours. tations with coatings], I think you have to come SCISCIANI: On the coating end, if it’s a thin- Photos courtesy of Cuviello to the architects or building owners and deter- ner film thickness that we’re putting down, it Concrete. mine what their expectations are for a finished will mirror the surface. So if you have concrete floor. And a lot of times it’s, do you recommend that has some pitting and stuff like that, it’s a thin-filmed system, a high-build system, ag- going to mirror it. If you go with a colored gregate or colored-flake system or a quarter- flake, one-eighth inch or up, a lot of times it inch resurfacing system. If it’s old concrete, it’s will mask those issues. 12

If you’ve got a real damaged floor, then CUVIELLO: What is getting popular in the pol- that’s when you get into resurfacing. The prob- ished concrete industry is three-eighths-inch ce- lem we see with resurfacing is that you’ll get mentitious self-leveling toppings. These toppings trowel marks. So, when [setting] customer ex- are applied over existing concrete and then pol- pectations, a lot of times we’ll say, with the ished. We’ve used them successfully, but basically resurfacing material, you’re going to see some it’s going to double the cost of the project. trowel marks; it just happens. If you want a SCISCIANI: What do you do, come in and smoother looking floor, then that’s when you blast [the surface] and then put on a three- go to a build-up type system. eighths-inch overlay? CUVIELLO: We come in and basically shot- blast it. Then we put epoxy down and then basically broadcast sand in it to rejection. We come back the next day, clean off the sand really well and then basically put a three-eighths- inch self-leveling material on top. Then we polish that. We just did an Old Navy where we were contracted to polish it. Once we got about halfway through the process, these footprints came out of nowhere, the shadowing of all of these footprints. Old Navy said “no way,” and made the contractor basically overlay it, and Coating is a good option for improperly cured concrete, a problem we polished it. polishing can’t hide. Photo courtesy of Cuviello Concrete. SCISCIANI: Why do they do an epoxy coat? CUVIELLO: For vapor barrier, and then also, when you see the sand, it creates a texture for that overlay to bond to. SCISCIANI: Interesting. Expensive, but interesting. CUVIELLO: It is expensive. We did two [retail] stores, and, I mean, we’re working in 50- , 60-year-old stores that have been modeled and remodeled and different floorings put down. Once the flooring came up and we polished the concrete underneath, it was a mess. They kept telling us, patch it, patch it, patch it. We patched it, and for what it was, it looked good. In some other areas of the country, [the retailer] said go ahead and put an overlay down. Now I can tell you what they paid us to Scisciani used decorative flake polymer coating on a corridor ramp and patch all of that area; it would have been less entryway to match polished concrete corridors. This project was expensive for them to just go ahead and over- completed at a university in Pittsburgh. lay it and polish it. Photos courtesy of Specialty Coatings & Consulting Inc. 13

D+D: What about maintenance for coated SCISCIANI: You did? I wasn’t keeping score vs. polished concrete? [laughing]. You had the better camera angle, too. SCISCIANI: Didn’t we cover this [in the D+D Once a [coated] floor is put down, there video], Jim? should be a six- to 12-month maintenance CUVIELLO: We did. I think I crushed you, [schedule] — meaning you should have the too. contractor or somebody come back in, inspect the floor. Especially if it’s a floor that has a lot of abuse or is constantly exposed to water. Damaged areas should be repaired promptly, because if the coating’s been damaged, water will get underneath and start to break the bond. In a water situation, we recommend every three to six months. A coated floor should be cleaned, degreased, either by dry or wet mopping. A floor scrubber, with soft bristles or pad, is also an effective way to clean. In areas where there’s a lot of grease, a lot of dirt, we recommend they just deck brush it and use a wet vac, depending on the non-skid [treatment] that’s on the floor. (above) The coated concrete floor of the Frick Car and CUVIELLO: I think that’s where polished con- Carriage Museum in crete really shines, again, in the right applica- Pittsburgh looks as good as tion. For example, with a VCT floor, there’s a cost new more than a decade after in buying floor finish, there’s a labor cost in ap- being installed. Wet and dry mopping have been the only plying the floor finish, there’s a labor cost in bur- maintenance. Photo courtesy nishing the floor finish to restore its shine. Now of Specialty Coatings & to maintain polished concrete you still want to Consulting Inc. burnish it, but instead of burnishing it maybe (middle) For a coated floor subjected to liquid, like this once a week, you’re going to be burnishing it carwash at a Honda once a month or maybe once every other month dealership in Pennsylvania, depending on the amount of traffic. Scisciani recommends With polished concrete, again, you sweep it maintenance every three to six months. Photo courtesy of or vacuum it, and then you mop it or autoscrub garagecoatings.com. it or some [other] type of a wet clean process, (bottom) Coated concrete and then you burnish it. The dry debris removal with decorative colored and the wet mopping should be the same flakes can create eye- catching effects, as at this amount of work no matter what surface it is. Kansas church. Using epoxy SCISCIANI: Good point. That’s where I’m with decorative flake going to crush you [laughing]. broadcast into it and a CUVIELLO: Bring it on [laughing]! polyurea topcoat, the 30,000-square-foot floor SCISCIANI: No, I agree with you. You features a large compass at know, D+D did that article on [my work at the the entrance. Frick Car and Carriage Museum; Photo courtesy of January/February 2013 issue]. That floor’s garagecoatings.com. 14 been down for 12 years, and, other than dry coated floor, but you still get the polished look. mopping and wet mopping, that’s all they’ve CUVIELLO: Exactly. done. It still looks like the day we did it. Penetrating treatments have been around in CUVIELLO: Again, I think that goes back to, the “concrete” industry for a long time, but the with any segment of the floor industry, No. 1, “polished concrete” industry has been domi- the preparation was done correctly up front. nated by a product that was designed to pen- And No. 2, the right product was specced for etrate and “micro” film on the surface, thin the application. enough you could not tell it was there. Two SCISCIANI: Right. The environment is foot things happened within the industry: Contrac- traffic and there’s cars sitting on it, so the ma- tors over-applied these products and created terial was designed for stain resistance. And a heavy film, barrier, coating; and some man- again, it’s about a 60-mil system, so it’s really ufacturers’ products did not penetrate as well not a thick system. But for that application, that and laid more on the surface and not in. was a properly designed system. The Concrete Polishing Association of Amer- ica at World of Concrete this year came out D+D: What about protective treatments — with a set of definitions to define the different are they necessary for polished concrete ways to make concrete shiny. [See “Defining floors? the Undefinable,” page 40.] CUVIELLO: There’s something in the industry SCISCIANI: I think that’s the sad part that I called guards. Basically it’s an acrylic-type find with what I’ll call the epoxy floor coating floor finish. I would say 90 percent, maybe 98 industry, is there’s not an organization like the percent of the time, they’re [over-applied]. CPAA setting guidelines. I mean [there are] ab- They’re designed to fill in the fractures and the solutely no guidelines in the coating industry. micropores and microfilm on the surface. But That’s what we fight everyday, trying to fig- you know, to put them down that way can be ure out what’s best for the customer, what’s difficult if you don’t have a lot of experience going to give them long-term [performance], with them. but yet, what’s going to get us in and out of a The one thing that I do believe you’re going job. We complete a number of floor projects to start seeing in the industry is a lot of these where the customer gives us the floor Friday companies looking towards the stone indus- evening and it has to be ready for use by Mon- try to see how they’ve protected porous stone day morning. That gives us a very short win- over the years. And I believe what we’re dow, so it limits the materials that we can use. going to start seeing are products that are de- CUVIELLO: The other thing that we run into signed to penetrate and protect from within — Phil, I’m sure you run into it too — is that the instead of creating a barrier on top. Because best product may be too expensive or out of the second you over-apply a guard, or mis- their budget. Although the proper specification apply it, what ends up happening is your for them is out of their budget, you know, you wear surface is no longer the concrete, it’s don’t want to walk away from the job. that guard. And that’s where this industry has SCISCIANI: I’m very careful with that, Jim, run into some problems. because a lot of times you deal with a customer SCISCIANI: Kind of like the hybrid polished and then six months down the road they’re concrete look, where some people are [polish- complaining because it’s not performing the ing the floor and then putting a clear way they want. I’ve gone back three or four polyurethane over top of it]? So in a sense it’s a times to fix a problem where I know it should 15

have been an eighth-inch system, a double CUVIELLO: It is a very, very slippery slope to broadcast system, but they only wanted to pay walk, and when we do it, we make sure we for a sixteenth-inch system. So now I’m kind of cross our t’s and dot our i’s and overempha- stuck under warranty, even though I told them size everything and document everything. up front, we need to do it this way. It’s one of Gina R. Johnson (gjohnson@durabilityand- those jobs I probably should have walked design .com) is editor in chief of Durability + away from. Design. D+D

Polished Need Not Mean Slippery It’s a common misconception: The shine that makes a polished concrete floor so beautiful, reflecting color and movement, makes it a threat for slips and falls. In fact, for both wet and dry environments, a polished concrete floor can be more slip-resistant than a coated concrete floor. According to Kevin J. Brown, manager of the commercial services group at KTA- Tator, “The slip resistance of polished concrete actually has a greater Kevin Brown, coefficient of friction [COF] than most coated floors considering a typical KTA-Tator specification for polished concrete.” In general, says Brown, a polished concrete floor has slip resistance that meets or exceeds industry standards of 0.5 or 0.6 COF. That’s because the flat surface produced by a fine polish puts the sole of the shoe directly in contact with the concrete surface. The level of slip resistance depends on the concrete polishing specification — the level of honing and polishing that’s done and the grit level of the tooling used. Protective film-forming acrylic coatings that are burnished into the surface, aka A variable incidence “guards,” can also be a problem when over-applied or misused. “They’re used to make tribometer is used to the floor pop and shine — and they do,” says Brown. “But they can make the slip resist- measure the coefficient of ance of the floor much less than if not applied, especially when [the floor is] wet.” friction on polished concrete. Photo courtesy of KTA-Tator Trouble also can arise when maintenance procedures aren’t followed, for example, if Inc. janitors wax a polished floor to enhance its appearance. Wax can be problematic for slip resistance. Manufacturers typically recommend a mild, neutral-pH cleaner. Entry mats can help to trap dirt and water from being tracked onto the surface. And of course, it’s important to clean up any spills immediately. 16

By Walter Scarborough, HALL Building Information Group, LLC

Editor’s Note: This article appeared in D+D in January 2012.

A combination of dyeing and polishing produced the color and shimmer of the concrete floor surface of the Rothwell Student Center at the University of Wisconsin’s Superior Campus. The color was supplied by an acetone dye in “Inca Gold,” while PROSOCO Inc.’s Consolideck® LS® Hardener/Densifier was used in the polishing process. A micro-thin protective coating of Consolideck® LSGuard®, applied with high-speed burnishers, gave the floor extra protection and gloss. Collaborating on the project were Specialized Inc. and D&B Industrial Floor Coatings, both based in Wisconsin. Photo by Shawn Wardall, Specialized Inc.

Crunching the Numbers on Polished Concrete, Other Flooring Types

olished concrete has gained a great deal of traction in design and construction, P thanks to the technology’s quickly- earned reputation as a sustainable, durable and aesthetically appealing flooring option. 17

But how does polished concrete stack up This matter of maintenance against other flooring solutions in the big pic- While much has been written about specifying ture of economics and performance, when and installing polished concrete floors, not much considered in terms of long-term cost and has been said about the necessary maintenance. maintenance issues? So, what exactly is the cost of polished Polished concrete—more specifically, concrete? bonded abrasive polished concrete—has be- While the initial cost is typically less than most come amazingly popular in recent years, with other flooring solutions, this is only part of the explosive growth in its use in virtually every evaluation when considering the life cycle of building type, both residential and commer- flooring solutions. The other part of the equa- cial. Polished concrete is favored by many tion, also of significant importance to many building owners and design professionals in building owners, is the cost in terms of actual lieu of traditional applied floor coverings. expense, along with attention and effort re- A number of reasons can be cited as to why quired to maintain the polished concrete floor. polished concrete is favored, but two reasons As for the prevailing misunderstanding that frequently are seen at the top of the list. polished concrete is maintenance-free, it First, among the various flooring solutions should be emphasized right at the top that available, polished concrete is one of the least there is no such thing as a flooring solution that expensive flooring systems over the service life requires zero attention. of the floor. To effectively evaluate the maintenance cost Second, a perception exists that there is no cost of polished concrete, we should look at the for maintenance when compared to terrazzo, other common floor coverings and their main- vinyl, carpet, and ceramic tile. Many building tenance costs. owners and design professionals believe that pol- It is difficult to develop a single general cost ished concrete floors are maintenance-free and for every floor covering because of variations that the polished finish will last indefinitely. connected to location, building type, quality of Unfortunately this is not entirely true. This be- It is difficult to arrive at a floor coverings, traffic volume, attention to lief results in frustration when a polished con- single general cost for every maintenance, and all the things that happen type of floor covering. crete floor appears to lose its luster. on or over a floor. One of the most extensive studies of initial and maintenance cost of floor coverings was carried out by the National Terrazzo Manu- facturers Association (NTMA) and published as the Terrazzo Cost Calculator. According to NTMA, this study was based on a survey of a number of buildings across the U.S., and it used a typical corridor in a commercial building as the basis of evaluation. The country was divided into eight zones in order to localize the cost, so the range shown in the charts below is least cost to most cost, based on the zones. For purposes of simplicity, the information presented below only extends through 10 18

years of the life-cycle cost. Maintenance comparisons While polished concrete was not included in Now let’s take a brief look at the requirements the NTMA study, there are other sources of cost for maintaining the various floor coverings that figures that can be cited in order to make a were included in the NTMA study. This infor- comparison, as shown here. mation is generalized because, like cost, many Three impacts on floors dominate the con- variables influence the amount of maintenance cerns of most owners: scratches, stains and loss attention that is necessary. of sheen. Dust, dirt and fine grit can act as For example, floors immediately adjacent to sandpaper when people walk on the floor or entrances will require more attention than when wheeled carts are moved across the floors in more remote areas. Floors in a popu- floor. This action creates small scratches that lar department store will require more atten- dull the finish of every floor type—no flooring tion than floors in a dentist’s office. Paths tend solution is immune. to develop across floors due to objects such as Over an extended period of time, this dulling process accumulates, and if the floor is not shelving units that channel foot traffic in spe- maintained, an unsightly appearance may re- cific directions. sult, especially if a shine is important to the To achieve the maximum life of a flooring fin- These costs were compiled look of the floor. If not dealt with on a routine ish or covering, several proactive activities are from the following sources: basis, damage can occur and, depending on essential to have in place. Concrete Polishing Association of America; Titus the flooring type, replacement or restoration First, it is important to have a maintenance Restoration; and Concrete becomes necessary. plan in place that is specifically designed for Network the flooring type, the amount of traffic that will 19

Dust is one of the most significant problems with maintaining floor finishes.

cross the floor, and the daily activities that will • Daily: Sweep using a yarn-wick brush treated occur over the floor. with sweeping compound, along with hand Second, while all stains cannot be prevented, working of stubborn stains and scuff marks with it is essential that when a spill does occur it is re- neutral cleaner diluted in warm water. moved immediately and the affected area • Weekly: Damp mop lightly soiled floors with cleaned. If spills are not removed promptly, the neutral cleaner. Heavily soiled floors should be floors become unsightly and more aggressive re- scrubbed with a mechanical buffing machine moval or restorative methods may be necessary. and neutral cleaner. Residue should be Third, it is prudent to use walk-off mats at mopped up with clean water before it dries; building entrances and other locations to pre- this is allowed to dry, followed by buffing with vent dust, dirt and fine grit (particulate) from a dry brush. being brought onto the floor. • Semi-annually: Strip old sealer and any fin- Terrazzo: While epoxy terrazzo does not re- ish coats. Reseal a clean floor. quire a sealer, Portland cement terrazzo re- Vinyl: A major vinyl sheet and tile manufac- quires a water-based acrylic sealer to protect turer recommends the following general main- the exposed Portland-cement portion of the ma- tenance procedures. trix, which is about 30% of the exposure. NTMA • After initial installation: Sweep, dust mop or provides the following minimum recommenda- vacuum to remove loose dust and dirt. Remove tions for maintaining terrazzo floor finishes. dried adhesive residue with mineral spirits. • After initial installation: While not required Damp mop with a neutral detergent. Apply for wear protection, as an option NTMA sug- two coats of a high-quality commercial floor gests a high-luster finish on top of the sealer to polish; a high-quality stain-resistant sealer be- achieve a desired sheen. These normally re- neath the polish should be considered in areas quire the added expense of spray-buffing to of high traffic, high soil load and areas where maintain the sheen. staining potential is high. 20

• Preparation for commerciral traffic: Scrub • Restorative maintenance-stripping: Scrub with a neutral detergent solution and a scrub- with a diluted stripping solution using a single- bing pad or equivalent brushes. If badly soiled disc floor machine equipped with a scrubbing and/or scratched, strip the finish with a strip- pad or equivalent scrub brush. Remove the ping solution. Thoroughly rinse the floor with dirty stripping solution with a wet vacuum or fresh, clean water and allow it to dry. Apply mop. Thoroughly rinse with fresh, clean water three to five coats of a high-quality commer- and allow it to dry. Apply three to five coats of cial floor polish; a stain-resistant type should a high-quality commercial floor polish; a stain- be considered in areas of high traffic, soil load resistant type should be considered in areas of and staining potential. high traffic, soil load and staining potential. • Daily/regular: Sweep, dust mop or vacuum Carpet: The Carpet and Rug Institute (CRI) daily to remove dirt, grit and soil that can sees a big difference between cleaning and damage the floor and become ground into the maintaining carpet. Cleaning is the removal of surface. Damp mopping should be performed apparent soil, and maintenance is a scheduled on a regular or daily basis depending upon ongoing process of soil removal designed to the traffic and soil levels. A neutral detergent maintain the carpet’s daily appearance at a can be used. consistent level of cleanliness. CRI suggests a • Periodic: When needed, scrub the floor with customized, comprehensive carpet-care pro- a neutral detergent using a single-disc (300 gram that consists of the following five elements: rpm or less) or automatic floor machine and • Soil containment: Isolation of soil entering the appropriate scrubbing pad or equivalent the building using mats at entrances. brushes. If using a single-disc floor machine, Vacuuming: Scheduled frequency, usually remove dirty cleaning solution with a wet vac- daily, for removal of dry soil using a CRI-ap- uum or mop. Thoroughly rinse the floor with proved “Green Label” vacuum. fresh, clean water and allow to dry. If sufficient • Spot and spill removal system: Using profes- polish (three to five coats) remains on the floor, sional spot removal techniques. buff, spray buff, or burnish to restore gloss. If Cleaning a sheet vinyl floor Interim cleaning: Scheduled-frequency ap- with soap and an automatic needed, additional coats of floor polish may pearance cleaning for all traffic areas. floor machine. be applied. • Restorative cleaning: Scheduled-frequency deep cleaning to remove residues and trapped soils. Porcelain tile: Porcelain tile is unique because of its high density and low water absorption attributes, which means it does not usually require sealers or waxes (actually, surface coatings may negatively affect the performance of the tile). • After initial installation: Completely remove grout residue and construction dirt. • Regular maintenance: Most tile manufacturers recommend a regular maintenance routine consisting of the following steps. — Remove debris from the tile by sweeping with a soft bristle broom or vacuuming. 21

—Spills should be wiped up as quickly as water with a wet vacuum or mop. Thoroughly possible. rinse with clean water and remove with a wet — Apply cleaner to tile and allow cleaner to vacuum, mop, or towel. remain on the tile for a short period of time. For unpolished tile, scrub with a nylon pad or Polished concrete soft bristle brush, or for more heavily soiled Contrary to the prevailing perception, a pol- floors use a floor machine equipped with a ished concrete floor does require some main- nylon pad or bristle brush. For polished tile, tenance attention during its service life. wipe or mop with a nonabrasive mop or cloth. Polished concrete is not indestructible, nor — Remove the dirty cleaning solution and can it be maintenance-free throughout its useful life. The consideration of primary importance is that polished concrete floors do not require the magnitude of maintenance attention that other floor coverings command. If maintained properly, polished concrete floors should provide years of satisfactory performance under whatever conditions prevail. A prominent concrete-polishing and polished-concrete restoration company with a national reputation gives the following general recommendations for maintaining polished concrete floors. It should be noted that these are only general recommendations; each polished concrete floor requires a specific maintenance program that is suited to that particular floor. • After initial installation: As an option, the finish on polished concrete floors can be protected by a stain guard, which can be a sacrificial layer; this will protect the floor from scratching, mild acids, spills, and stains. Daily: Dust mop; depending on the volume of traffic the floor may also need to be wet- mopped or autoscrubbed. Spills should be removed immediately and the floor cleaned. For example, if not removed immediately, acidic food spills such as pickle juice or tomatoes can cut through the stain guard and damage the polished concrete floor surface. • Weekly: Mop or autoscrub with clear water. • Monthly: Mop or autoscrub with clear water; using a neutral-pH soap if needed and rinsing after. • Quarterly: Mop or autoscrub with clear 22

water; using a neutral-pH soap if needed and lished that takes into account how the floor will rinsing after. be used and the level of use anticipated. • Annually: Mop or autoscrub with clear water; using a neutral-pH soap if needed and About the author rinsing after. Optionally, high-speed burnish Walter R. Scarbor- using a diamond-impregnated maintenance ough, CSI, SCIP, burnishing pad. AIA, is Dallas re- • Three years: Mop or autoscrub with clear gional manager of water, using a neutral-pH soap if needed and Charlotte, N.C.- rinsing after. This may be the time to apply a based HALL Building stain guard and burnish with a high-speed Information Group burnisher using a high-grit diamond-impreg- LLC, and offers specifications consulting, man- nated burnishing pad. ufacturing consulting, and peer reviews. He is • Five years: This may be the time to repolish a contributing editor of Durability + Design, with high-grit bonded abrasives. Mop or au- and is a registered architect and specifier with toscrub with clear water; using a neutral-pH more than 30 years of technical experience Depending on usage, polished soap if needed and rinsing after. Apply addi- with many building types. He was director of concrete may need to be tional coats of a stain guard and burnish with specifications for 10 of his 22 years with one swept daily. a high burnisher using a grit diamond im- of the largest architecture firms in the world. pregnated burnishing pad. Scarborough is revision author for CSI Proj- Throughout the life of the polished concrete ect Delivery Practice Guide; co-author of the floor, it is relatively simple to rejuvenate the college textbook Building Construction, Princi- floor by applying additional coats of the stain ples, Materials and Systems; has written arti- guard, burnishing or repeating the last couple cles for periodicals; has taught college courses; of steps of the polishing process using fine- has given presentations at local, state, re- bonded abrasives. gional, and national conferences; is active in the Construction Specifications Institute at na- It’s complicated tional and chapter levels; is a past president of We hope this article has provided a general the Dallas CSI chapter; is a member of the In- look at how bonded abrasive polished constitute Education Committee; has CDT, CCS, crete floors compare to other flooring solutions and CCCA certifications from CSI; received in initial cost and maintenance. As stated at CSI’s J. Norman Hunter Memorial Award in the outset, each floor is located in a unique set- 2008; and is an ARCOM MasterSpec Archi- ting and a maintenance plan should be estab- tectural Review Committee member. D+D 23

By Howard Jancy, Jancy & Associates

Editor’s Note: This article appeared online in February 2012.

This standard gray concrete slab is polished and colored with water-based dyes. Photo courtesy Decorative Concrete Institute

ARTISTRY AND CHEMISTRY: Color Theory and Practice with Polished Concrete

lmost two decades ago, colored emerged as a major force in current ap- concrete flooring found its way proaches to the coloring and treatment of hor- Ainto the lexicon of architects and izontal concrete. interior designers. As topical concrete color- Chemical stains are utilized, in addition to ing was rediscovered, designers realized that dyes with their wide range of colors, for color- a dull and lifeless-appearing concrete slab ing polished concrete floors. Even though top- could be enlivened with natural colors and ical coloring technology is well known, imaginative tooling. understanding the qualities of the available Today, topically coloring concrete floors recoloring products, as one of the many impor- mains in vogue, but the popularity of mechan- tant components of polished concrete, is im- ically processed or polished concrete has portant to managing expectations. 24

The materials UV stable, so applications near windows and The two most common topical coloring prod- skylights are potentially problematic. ucts for concrete are chemical stains and dyes. Some manufacturers provide dyes with UV Each system offers a unique palette of colors stabilizers or a densifying dye (color and den- and to a degree, yield similar results—translu- sifier combined into one product) to enhance cent, variegated and mottled colorations— color longevity. The practicality and effective- often compared to the natural color variations ness of these color-stabilized systems should found in stone or other natural materials. be discussed with the contractor and supplier. Chemically reactive stains react with the ce- Reactive stains and dyes are used on existing ment in the concrete to form a limited number and newly installed concrete floors. On proj- of earth-tone colors. The coloring reaction, ects where a new concrete floor will be in- which is often unpredictable and surprising, stalled and polished after curing, another even with the construction of a pre-job mock coloring option is a coloring admixture added up, can differ across the concrete’s surface, po- to the concrete during mixing. Providing some tentially creating a high level of color variation. colors similar to the stains and dyes, integral In contrast, dyes are pigment concentrates concrete coloring offers advantages over top- mixed with water or acetone, and are not de- ical coloring agents, such as shortening the pendent on the concrete’s chemistry to produce time required to polish the concrete and im- color. Since dyes do not react with the concrete proved color durability. substrate, results are more consistent and truer to the color chart, which some may consider Choosing the color The Bartow County Civic an advantage over reactive stains. Center in Cartersville, Ga., For the most part, contractors initially supply features a polished and dyed Though some of the earth-tone colors avail- color charts and project photos to illustrate the concrete floor installed by able from dyes are visually similar to those various color options. Once color choices are CSolutions (Norcross, Ga.) produced with acid stains, more colors—par- Photo courtesy American determined, often dictating the possible product ticularly vibrant color choices—are available Society of Concrete alternatives, contractors will typically discuss with dyes. Not all dye colors and products are Contractors the pros and cons. This is key to managing expectations of the selected system relative to the desired project outcomes. Contractors’ insights on product selection are often based on per- sonal preference and experience, yet there is a common thread of opinion from polishing contractors we spoke with for this article.

New concrete When installing a new concrete floor, integrally coloring the concrete during mixing is preferred over topically coloring the concrete during the grinding and polishing process. Once a coloring admixture is added to concrete, it requires no additional labor to install, whereas topical stains and dyes require additional labor to apply and remove residues. Integral concrete colors are also considered more durable rela- 25

tive to UV exposure and heavy use or traffic, are only available in eight to 12 colors, since the color is full depth, compared again to whereas dyes offer a wide range of colors, in- stains and dyes, which concentrate color only cluding many bolder and brighter hues. Even near the concrete floor’s surface. custom colors are possible with dyes. Another consideration for using integral Once a color is chosen by a project owner, color for new concrete is ease of repair. Topi- contractors will review other considerations as cally applied colors do not penetrate deeply to the best product (remember managing ex- into the surface; even moderate scratches may pectations), particularly if the color choice is remove the color, making repairs more chal- available as either an acid stain or dye. An acetone-based dye in an lenging (particularly if using an acid stain) The contractors we spoke with tended to be in amber color was applied to compared to the full-depth color provided by agreement that chemically reactive stains are this floor with a hand-pump an admixture. So, integral color can save time more durable than pigment-based dyes. Hard- sprayer. Acetone-based dyes and money when installing, processing and were used, instead of ened concrete contains numerous small pores. water-based dye or acid maintaining the polished concrete floor. Mechanically processing concrete opens the stain, because acetone pores at the surface, allowing the topical color evaporates quickly, Existing concrete to penetrate, and depth of penetration is solely eliminating color bleeding For an older concrete floor in good physical under painters’ tape. a function of the concrete’s natural porosity and Photo courtesy Superior and visual condition, acid stains and dyes are how well the surface has been opened by Polished Concrete LLC the product choices. Generally, chemical stains grinding and honing. At this point stains and dyes tend to penetrate equally well. When the chemically reactive stain is applied, however, it reacts with the calcium hydroxide, produced during cement hydration to create the color. Consequently, the resulting color is “fixed,” or bound in the concrete pore structure, contributing to its durability. Dye colors, on the other hand, are formed by pigment that is retained in the concrete pores after the water or acetone carrier dissi- pates. The pigments are not as strongly bound as a stain color, not only making the color more susceptible to degradation from traffic, but also to rising moisture vapor. On a heavily used commercial floor, an acid stain might be the preferable coloring product and process. It should also be kept in mind that issues with UV stability must be considered in weighing dyeing versus staining. Acid stains are great products, but they are not without their quirks. As already mentioned, depending on the concrete’s mix design and chemistry, a stain color can exhibit considerable variation, sometimes faintly resembling the color chart or the result achieved on a previous installation. Stains are UV stable. 26

Green and blue stains, however, are prone Stain residues should also be removed prior to darkening, even to the point of turning black to polishing so as not to diminish the effective- when repeatedly exposed to moisture. This ness of the resin-bonded diamond abrasives. could be a problem for the floor area under a Stain applications are potentially more time- drinking fountain, near a sink or toilet, or even consuming and labor-intensive than a compa- from periodic wet mopping, if the floor is not rable dye application, adding to the cost and sealed and maintained. duration of a project. Once an acid stain is applied, most manu- Dye products dry quickly, so evaluating the facturers recommend a dwell-time of several coloring effect is rather quick, as is application of hours for the stain to react completely to cre- more dye if needed. Dye residues are also ate the desired color. Multiple applications quicker and easier to remove than stain residues. may even be necessary to attain an approx- imation of the color chart. Often, the stain Using stains and dyes together AmeriPolish dyes were used residues must be removed from the surface Interestingly, many contractors will utilize both to create this multi-colored for an accurate evaluation of the color before chemical-stain and dye products on the same polished concrete floor. determining if additional stain is needed on project. Often, a stain may yield an unsatis- Photo courtesy AmeriPolish the floor. factory result on portions of the floor, and a Inc. dye of the same color will be used to touch up the marginal stain color. Another opportunity for dual use is on a previously stained floor that now requires recoloring. Imagine a food spill—vinegar, pickles, tomato sauce—on a polished concrete floor in a grocery store. Thorough cleaning will not only remove some of the stain color, but also may render reapplication of a chemical stain ineffective since there is now insufficient calcium hydroxide in the concrete to initiate a chemical stain reaction. Here again, a dye is a logical choice for the repair. What about water-mixed dye compared to an acetone-mixed dye? Again, many good opinions are heard on this question, and all carry validity, depending on the job. If indoor air quality and flammability are a concern, then the obvious choice is a water-based system. If the environmental concerns are not an issue, then acetone-mixed systems offer many advantages, for the following reasons. • Acetone “flashes,” or evaporates quickly, allowing for quicker evaluation and reapplication of the dye prior to polishing. • Rapid evaporation minimizes the risk of color bleeding across a saw-cut joint or under 27

AmeriPolish dyes were used to create this polished concrete floor. Photo courtesy AmeriPolish Inc.

masking tape into the adjacent surface when ance from light to dark gray. Self-leveling over- installing logos, graphics, grid patterns, and lays also are available in white and light gray. similarly detailed compositions. Also, when grinding aggressively and signifi- • Acetone is less dense than water, so it may cantly exposing the aggregate, the aggregate act as a better carrier for the pigments into a color will alter the perceived color of the stain tightly closed concrete surface. or dye. A mock-up is always advisable to de- • Acetone readily penetrates through stain- termine the substrate’s effect upon final color. guard products and sealer residues in the concrete’s pores, making the dye more effective for Problem concrete repairs and touch up Floors that are in good physical and visual con- • Acetone dyes produce slightly darker colors dition are the best candidates for processing of than water-based dyes of the same color. concrete with coloring and polishing. Some ex- Other solvents such as alcohol or lacquer isting concrete floors may not be effectively thinner may also be useful. These types of sol- treated; this may include concrete floors that vents would be used since they evaporate more have been excessively patched or trenched, slowly than acetone, potentially allowing the were constructed with different concrete mix de- pigmentation to penetrate deeper into the con- signs, exhibit random wear patterns, were in- crete’s surface pores. consistently finished during original installation, Regardless of the topical coloring product cho- or show shadows from prior contamination. sen, the colorations produced by acid stains and These surfaces will yield less-than-satisfactory dyes can look different, depending on the color results when colored and polished. of the substrate. Concrete can range in appear- For these conditions, a viable option is resur- 28 facing the floor with a cementitious overlay, Floors, by Jason Barnes, The Construction typically installed at a thickness ranging from Specifier, August 2011. one-fourth to three-eighths of an inch, and once cured, proceeding with mechanical pro- About the author cessing. Overlays are pre-packaged products, Howard Jancy, CSI, generally are available in a white and light CDT, is president of gray color, and can be integrally colored or Jancy & Associates, an topically colored with a stain or dye. architectural-consultant Also, decorative-mineral aggregate or col- and manufacturer’s- ored recycled glass can be incorporated into representative firm the overlay, exposing the colorful additions based in Chicago. He during polishing. has more than 22 years of experience in the It should be noted that the existing concrete decorative-concrete business, in sales, train- must be thoroughly prepared before installing ing, technical service, architectural promotion, an overlay. Again, the owner, designer or specifications, technical writing, and new- specifier should consult with the supplier and product and business development. Jancy & contractor, since not all overlays are alike. Asssociates provides representation for build- Some products may be more suitable than oth- ing-material manufacturers and specialty con- ers when coloring and polishing. tractors, creating greater visibility within the design community and opportunities for in- The challenge of managing creased sales. expectations Jancy is a member of the CSI Chicago chap- There does not seem to be one coloring prod- ter and is chairman of the chapter’s Industry uct that will perform ideally on every job. The Round Table, which offers professional-devel- answers are not always black and white; opment seminars for members. He conducts sometimes there are gray areas, even with pol- an annual class about AIA-compliant pro- ished and colored concrete floors. But by un- grams for architectural continuing education. derstanding the similarities and differences He has written articles for a number of indus- between the various coloring materials, color try publications, including Concrete Decor, and product selection can be a more informed Landscape Contractor National, Journal of and accurate process giving you confidence Architectural Coatings, Construction Specifier, that your colored polished concrete floor will and Concrete Construction. meet your expectations. Jancy has a bachelor of science degree from the University of Illinois, is an ACI certified References Concrete Technician, and is certified by CSI as 1. Out of the Stone Age: The Evolution of Dec- a Construction Documents Technologist (CDT). orative Concrete Continues to Stretch the Hori- He was a founding board member of the Dec- zons for an Ancient Building Material, by orative Concrete Council and has been an af- Howard Jancy, D+D News, July 2010. filiate member of the National Ready Mix 2. Concrete Stains and Dyes: Surveying the Concrete Association (NRMCA), the American Color Spectrum, by Howard Jancy, Journal of Society of Landscape Architects (ASLA), Amer- Architectural Coatings, March-April 2009. ican institute of Architects (AIA), and the Amer- 3. Nine Fundamentals for Polished Concrete ican Concrete Institute (ACI). D+D 29

By Howard Jancy, Jancy & Associates

Editor’s Note: This article appeared online in September 2012.

Photo courtesy of Metzger/McGuire

KEEPING THE SHINE: Basic Training in Maintenance of Polished Concrete Floors

ellooooo! Is anybody listening? Too often, I hear myself saying that when, for the umpteenth time, I am discussing the mainte- H nance requirements for a polished concrete floor with an owner and his or her representatives. Previous discussions—forgotten, ignored or selectively applied—have evolved into a job complaint, with accusatory fingers pointing at the concrete, at the polishing equipment, at the chemicals, or at the contractor. So now, for the umpteenth + first time, let’s again discuss polished concrete maintenance. 30

What Is Polished Concrete? application that positively contributes to the Suitable for older concrete, as well as newly aesthetic longevity of the floor. A protective placed or constructed floors, polished concrete micro-film can also be applied for stain resist- is the product of mechanical processing and ance and cleanability. chemical treatments. The mechanical process is a series of stages Stages and Steps referred to as grinding, honing, and polishing Grinding with metal-bond, 50-grit or lower (GHP), progressing from coarser to finer dia- abrasives is the most aggressive stage, open- mond abrasives appropriate for each stage of ing the surface and removing minor pits and the process. blemishes, some stains and sealer residues. The goal of progressing to finer grits in each Grinding is also used to expose the sand and stage is to achieve maximum refinement; that larger aggregates near the concrete surface, if is, to remove the scratch or abrasive marks in- that is the desired look for the finished floor. troduced by the coarser grits. In simple terms, Grinding can be thought of as preparation for GHP processing levels prepare, smooth and fi- honing and polishing, physically opening the nally shine concrete flooring. concrete floor to a desired level, thereby creat- The processed concrete is chemically treated ing a range of appearances, from a sanded or with a liquid hardener to enhance its surface salt-and-pepper appearance up to a coarse ag- Photo courtesy of durability, reflectivity and gloss. It is a critical gregate appearance similar to terrazzo. Metzger/McGuire Honing utilizes resin-bond abrasives, ranging from about 100 to 400 grit. During this stage, the finer or less-aggressive abrasives in comparison to the grinding stage start to close the concrete surface, imparting a matte finish with a degree of reflection and sheen. This is also when a liquid hardener or densifier is applied, generally after the surface has been processed with a 200-grit abrasive. Finally, polishing is undertaken, using abrasives from 800 to 1500 grit—and sometimes as fine as 3000 grit—to achieve a highly reflective floor with mirror-like qualities. The liquid densifier reacts chemically within the surface pores of the concrete, producing a harder, denser surface that is more resistant to abrasion, dirt and some spills. The densifier also enhances the sheen produced by mechanical processing. Finally, a guard product (also called a stain protector) can be applied to further protect the floor from ketchup, vinegar, red wine, motor oil, anti-freeze and other common, damaging materials found in commercial buildings. When applied correctly, guard products form 31

an imperceptible micro-film in the surface pores ply a highly alkaline or acidic liquid (whether of the concrete that improves resistance to dirt a food or the wrong cleaning chemical), and and stain absorption. While the products are the perfectly polished surface will be dulled, effective against wet spills that could stain or etched, stained or even damaged. etch the surface, they are also breathable, al- Equally vexing is gritty material carried on lowing moisture vapor to leave the slab. the bottom of shoes, which scratches the floor. On the other hand, ignoring or minimizing Concrete Conundrum maintenance will also diminish the floor’s at- Misunderstanding the maintenance require- tractiveness over time. So the facility owner ments of polished concrete and putting the re- and cleaning personnel need upfront educa- sponsibility in the hands of those least tion about maintenance requirements. informed about the technology are generally Reviewing a maintenance manual is an ideal the root causes of a dull and lifeless floor. way to start a dialogue about how to conduct Polishing concrete is a very specific process. a maintenance program for polished concrete. It should follow, therefore, that maintenance is The table below, or some variation, might be also a specific process requiring the right a central feature of a maintenance manual. equipment, chemicals, timing, and a basic understanding of concrete. Maintenance Matrix Cured concrete has the strength to support Daily maintenance is important for high-traffic tall buildings or carry cars and trucks on a commercial floors, although residential floor- roadway; yet it also has an Achilles heel that ing may require less frequent care. The basic is often exhibited on polished floors: Hardened requirement of daily care is sweeping and dry- concrete is a reactive material. Spill or misap- mopping to remove dirt and grit that dulls the

Sample Maintenance Schedule for a Polished Concrete Floor 32

surface and, if left there, can even scratch or maintain other types of flooring are inappro- abrade the concrete over time. priate for polished concrete. Excessive scratches or deeper gouges could So the choice of cleaning products is critical: require more time and labor to correct, so daily Avoid anything acidic or highly alkaline, and attention to the floor can pay off longer term. substitute pH-neutral to slightly alkaline cleaning (On a preventive note: Walk-off mats at en- products. Your manufacturer or supplier of pol- trances or protective mats where there is con- ished concrete chemicals will often have specialty centrated foot shuffle, such as behind a service cleaning products designed for these surfaces. counter, are highly advisable. This is especially Conversely, using only water to clean pol- important in Northern climates, where salt and ished concrete can lead to problems in time. sand are used to remove ice and to prevent Neutral detergents contain surfactants or wet- slip-and-falls.) ting agents that help the cleaning solution pen- Weekly maintenance includes wet mopping, etrate the dirt and, most importantly, keep the which may be required more frequently, de- dirt suspended in solution, allowing it to be pending upon use of and traffic on the floor. more readily removed. Using water alone may Manual mopping using a mop and bucket is ap- allow the dirt to redeposit on the surface as the propriate for small or select areas of a larger water dries. floor, whereas larger floors, such as those found Educating cleaning staff about using appro- in box stores or warehouses, are best “mopped” priate cleaning methods and chemicals for pol- with a walk-behind powered scrubber. ished concrete is important. Frequent water changes are important when hand mopping. Dry mopping or vacuuming Keeping Up should always precede washing the floor. Wet spills of damaging foods and other substances should be cleaned up as soon as The Right Solution possible. The pH of the cleaning solution is important The guard product/stain protector applied when wet-cleaning a polished concrete floor. after mechanical processing provides only Many cleaning chemicals typically used to Photo courtesy of Jancy & short-term (hours) protection from these types Associates of spills. Left overnight, the spilled material can penetrate and blemish the concrete. Remem- ber, guard products do not create an impervi- ous film and are not intended to be sealers. Periodic dry and wet cleaning is the basis of the cleaning program. But even if the cleaning is done regularly, the polished surface can dull. To re-pop the shine, run a high-speed (1500 rpm) burnisher over the floor once or twice a month with micro-polishing pads that are impregnated with fine-grit diamond abrasives. This process should be done only after the floor is thoroughly cleaned of dust, dirt and grit, and then dried. After a point, however, even high-speed burnishing may not revive the polished concrete 33 to its original luster. At this time, re-application About the author of the guard product may be necessary. The Howard Jancy, CSI, CDT, guard is applied to a clean and dry surface is president of Jancy & using a micro-fiber, T-bar applicator. Associates, an architec- Do not apply excessively, creating a sealing tural-consultant and man- effect with the material. It is also important to ufacturer’s-representative note that the chemical composition of guard firm based in Chicago. products or stain protectors, as well as liquid He has more than 22 years of experience in densifiers, vary among manufacturers. Consult the decorative-concrete business, in sales, with the manufacturer or supplier of the chem- training, technical service, architectural pro- icals before embarking on a maintenance reg- motion, specifications, technical writing, and imen for your polished concrete floor. new-product and business development. Jancy & Associates provides representation for build- Diamonds are Forever ing-material manufacturers and specialty con- Diamond polished floors are almost forever, if tractors, creating greater visibility within the they are properly maintained. However, the design community and opportunities for in- floors could require rejuvenation every two to creased sales. 10 years. The frequency or necessity is obvi- Jancy is a member of the CSI Chicago chapter ously dictated by the amount and type of traf- and is chairman of the chapter’s Industry Round fic, and by the original finish, whether it is Table, which offers professional-development matte or mirror-like. seminars for members. He conducts an annual Traffic over the polished concrete will even- class about AIA-compliant programs for archi- tually dull and scratch the surface beyond the tectural continuing education. He has written ar- remedial capabilities of burnishing and re-ap- ticles for a number of industry publications, plication of the guard product. including Concrete Decor, Landscape Contractor Rejuvenation involves mechanical process- National, Journal of Architectural Coatings, Con- ing, similar to the initial GHP process. You’re struction Specifier, and Concrete Construction. likely not starting with aggressive grinding, but Jancy has a bachelor of science degree from rather with honing or polishing, depending on the University of Illinois, is an ACI-certified the scratch depth into the concrete. Rejuvena- Concrete Technician, and is certified by CSI as tion will also require re-application of the den- a Construction Documents Technologist (CDT). sifier and micro-filming guard product. Once He was a founding board member of the Dec- the rejuvenation is accomplished, the polished orative Concrete Council and has been an af- concrete floor is attractive and functional for filiate member of the National Ready Mix another 10 years. Concrete Association (NRMCA), the American Society of Landscape Architects (ASLA), Amer- ican Institute of Architects (AIA), and the Amer- ican Concrete Institute (ACI). The author would like to acknowledge Jim Cuviello, chairman of the Concrete Polishing Association of America’s (CPAA) Polished Concrete Maintenance Committee, which is developing guidelines for the maintenance and restoration of polished concrete floors. D+D 34

By Brad Burns, Concrete Polishing Association of America

Editor’s Note: This article appeared in D+D in November 2013.

This gleaming bonded abrasive polished concrete floor in a bank in Chester, Ill., shows why, despite challenges, the polished concrete flooring industry still grows. The floor is an example of CPAA’s level 4 finished gloss. Photo courtesy of L.M. Scofield Co. Defining the Undefinable Building a system that gets predictable results is the challenge for the growing, but un-standardized concrete-floor polishing industry

ince the gloss and gleam of polished concrete began to grow in popularity S about 13 years ago, architects, designers and contractors have struggled to specify and achieve predictable, uniform outcomes on projects.

Many architectural firms refuse to specify processing concrete surfaces. They’ve created polished concrete as a finished floor. They’re many procedures for polishing floors to shiny often uncertain of exactly what contractors can finishes. provide. The problem is that floors with “shiny fin- On the other hand, the sudden growth and ishes” are not always uniform in appearance popularity of polished concrete, along with ad- or performance. With the variations in vances in equipment and diamond-tooling processes and concrete, it’s no wonder pre- technology, has spurred many contractors to dicting the outcome of projects is difficult. develop faster, more economical means for Another problem is that some contractors 35

are almost superstitious when it comes to terms. If architects, designers and contractors choosing procedures, equipment or particular can speak a common language in the specifi- diamond tooling. When these fail, contractors cation process, then architects and designers often hit panic mode in searching for solutions. can more accurately explain what they want, When a sales technician offers the “perfect and contractors can more consistently provide solution,” which in fact does solve the immedi- it. ate issue, the contractor adopts this new prod- The CPAA defines “polished concrete” as uct or process as the latest, greatest and best, “the process of changing the concrete floor to be used on all projects. surface, with or without aggregate exposure, The contractor doesn’t realize that due to the to achieve a specified level of finished gloss many variations in concrete and on projects, using one of the listed classifications; Bonded this product or process will eventually fail as Abrasive Polished Concrete; Burnished Pol- well. Add an architect, designer or owner into ished Concrete; or Hybrid Polished Concrete.” this mix, and it’s understandable why some Bonded Abrasive Polished Concrete — The dark stripes on this projects lead to discontent, frustration and un- Bonded Abrasive Polished Concrete is the most newly poured 6,000-square- fulfilled expectations. common method for processing concrete. foot school addition bonded This repeatable and sometimes endless cycle CPAA defines it as “the multi-step operation abrasive concrete floor continues until the polishing technician learns resulted from an initial grind of mechanically grinding, honing and polish- that exposed aggregate how and why some products and processes ing a concrete floor surface with bonded abra- unevenly. This type of work and others don’t. sives to cut the concrete floor surface and to problem is often caused by refine each cut to the maximum potential to poor communication between Defining polished concrete design professional and achieve a specified level of finished gloss.” To help the contractor and the design team ef- polishing contractor, when a Most industry professionals are familiar with fectively communicate about the processes particular grind is specified, this simple yet detailed process of working rather than a specific used on projects, the Concrete Polishing Asso- through a series of diamond-tool grits to refine aggregate exposure. Photo ciation of America (CPAA) has defined “pol- courtesy of Brad Burns, the concrete and achieve a particular level of ished concrete” and other common industry CPAA. gloss. Burnished Polished Concrete — Burnished Polished Concrete became popular with “big box” retail project clients who wanted economical installation without high gloss and clarity, and who were prepared for the recurring maintenance cycles. CPAA defines Burnished Polished Concrete as “the multi-step operation of mechanical friction- rubbing a concrete floor surface with or without waxes or resins, to achieve a specified level of finished gloss.” This process starts with high-quality, engineered concrete tightly monitored for quality- control during placement and finishing. It improves the concrete’s appearance and durability with chemical hardeners, protective treatments and lightweight high-speed burnishers 36

Here, a surface-coated concrete floor suffers from exposure to the construction process, degrading its appearance. Communication and coordination up front between the general contractor and concrete flooring contractor can help prevent such problems. Photo courtesy of Brad Burns, CPAA.

fitted with diamond-impregnated buffing pads. Using the larger, heavier equipment to es- Hybrid Polished Concrete — Hybrid Pol- tablish the specified level of aggregate expo- ished Concrete is simply the combination of the sure, contractors were able to process the two other processes. concrete to where they could switch to the It came about as contractors, always seek- lighter, faster Hybrid Polished Concrete equip- ing faster and better methods, adapted ment and complete projects quickly. bonded abrasive pads typically used for This gave clients the glossy appearances Bonded Abrasive Polished Concrete to the they wanted at lower installation costs. lightweight, high-speed burnishers used for Burnished Polished Concrete. Complications and variables Using the more aggressive bonded abrasive However, it also complicated matters by adding pads, instead of diamond-impregnated buff- many more variables to the polishing equation. ing pads, with lightweight high-speed bur- Technicians who didn’t understand how and nishers on high-quality engineered slabs why couldn’t achieve consistent results. offered terrific results. However, results varied Polishing technicians unable to achieve what away from high-quality engineered slabs. the client wants often see the concrete surface Contractors found that depending on the as the problem. That’s not to say that concrete quality of the concrete, the method was limited placement and finishing doesn’t have a large as to how well it could expose aggregate and impact on the outcome of a project, but it’s not achieve clarity. always an excuse for a polishing technician’s They overcame that limitation by using lack of understanding or knowledge. heavy grinding and honing equipment from That’s why the CPAA uses the “specified level the Bonded Abrasive Polished Concrete of finished gloss” system to assist design teams process to create surfaces similar to the high- and polishing contractors in beginning proj- quality, engineered slabs that work so well for ects with a clear understanding of what to ex- the Burnished Polished Concrete method. pect for final outcomes. 37

Re-grinding and polishing to a Measuring gloss and clarity mond tool to achieve Finished Gloss Level 1. By specified class B/C salt and properly processing the concrete to meet the pepper exposure and level 3 Though important tools in measuring specified finish resolved the problems levels of shine, the CPAA has found using gloss minimum level of 20 on the DOI meter, you offer on the school addition floor meters alone for quality control on polishing your client a better floor with a longer life cycle. (page 35), once the new projects to be unreliable. This principle carries over to Levels 2, 3 and polishing contractor and the design professional Applying stain-protection products or using 4. Each level brings higher-quality clarity and communicated using a certain exposed aggregates in the concrete can gloss. When architects or designers specify common terminology and net short-term high-gloss readings without the Finished Gloss Level 4, they set the standard accepted standards. advantages of diamond tooling to refine the con- for very high-quality projects that require high Photo courtesy of Brad Burns, CPAA. crete surface to a long-term high gloss. levels of attention to detail. Gloss meters coupled with DOI (distinction For a Finished Gloss Level 4, polishing tech- of image) meters offer better quality control for nicians must understand from the start that re- polishing projects. DOI meters measure “clar- finement of each step is mandatory to meet the ity,” or the quality of the light reflected from the specification. flooring surface. That’s often what clients see The CPAA is seeing immediate results from when they describe high gloss. the new terminology and specifications. We’ve gotten many calls from architects, general con- Finished Gloss Levels tractors and polishing contractors about how Finished Gloss Levels are listed as 1-4, with the new terminology or a clearly written spec- varying degrees of clarity and gloss. ification has helped define designs for suc- Level 1 has low clarity and gloss levels, with cessful projects. a minimum of 20 on a DOI meter for clarity Concrete placement contractors have also and 15 using a gloss meter. It’s often described expressed approval of standardization of pol- as a ground or matte finish. ished concrete terminology. They’ve mentioned It still takes more than one pass with a dia- how they are better equipped to understand 38 what is required of them to attain a successful About the author polishing project. Brad Burns is the execu- The CPAA is still researching specific levels tive director for the of refinement to fully define Finished Gloss lev- Concrete Polishing As- els. Until then, we must rely on polishing tech- sociation of America nicians who have the knowledge of how and (CPAA). As one of the why to achieve consistent, uniform and speci- founding members of fied results. the CPAA, Burns has You can download a complete 03 3543 been instrumental in de- Bonded Abrasive Polished Concrete specifica- veloping standard procedures for the polish- tion from the CPAA website at http://con- ing industry. He has been in the flooring cretepolishingassociation.com. business for more than 28 years, and recently owned and managed a flooring company spe- cializing in polished concrete with his wife, Terry. He is a member of ASCC and ACI. Burns is active in several industry association com- mittees. He is an international speaker and teacher working diligently to train and educate contractors to better understand processes and become more successful. D+D