® 09 23 00/NGC

Gold Bond BRAND 09 26 13/NGC Resource Manual Table of Contents How to use We’ve even included a glossary of plaster terms and definitions. SECTION PAGE this Manual For technical inquiries, contact our & Plaster...... 3 Designed for contractors, architects and specifiers, this useful manual Technical Services Department at Gypsum Plaster Base and Metal Lath ...... 4 contains a broad range of helpful 1-800-NATIONAL (628-4662), or information about our lath and fax 1-800-FAX-NGC1 (329-6421). Conventional Plaster Accessories ...... 5 plaster systems and veneer . You can also access our Internet home page at nationalgypsum.com Basecoat Plasters ...... 6 Since conventional lath and plaster or nationalgypsum.com/espanol. differs from veneer plaster, we’ve Finish Plasters ...... 7 simplified the manual by dividing it Note: Further information on into two distinct sections. our plaster products is available Problems & Solutions ...... 8 in National Gypsum Company’s The first section contains descriptions Veneer Plaster ...... 13 Gypsum Construction Guide. of our gypsum plaster systems including Veneer Plaster System Components ...... 14 lath, metal accessories and plasters. You’ll also find construction recom- Veneer Plaster Accessories ...... 16 mendations to help you get the Recommendations ...... 17 most from this conventional finish. The second section, devoted to Problems & Solutions ...... 21 veneer plaster, features descriptions ® Glossary ...... 26 of our products including Uni-Kal , X-KALibur® and Kal-Kote®, along with a comparison of one-coat and two-coat systems. In both sections, we look at unique conditions common to plaster finishes, and we recommend solutions to these problems.

2 Lath & Plaster 09 23 00/NGC

Features/Benefits Recommendations m Provides a smooth, high quality m Control joints should be installed surface in ceilings without perimeter m Requires no joint taping and relief with a maximum distance finishing between joints of 30' with a maximum undivided area of m Resists nail pops better than 900 sq. ft. With perimeter relief, gypsum wallboard the maximum distance between m Enhances overall wall strength joints is 50' with a maximum undivided area of 2500 sq. ft. m High impact and abrasion On side walls, control joints resistance should be installed every 30'. m Masks components and m Where dissimilar plaster bases mechanical service areas adjoin, use strip-metal lath with Selecting 15 lb. felt paper between the Plaster Bases metal lath and underlying base. m National Gypsum Company manu- Carefully inspect all lath and fur- factures all of the most common ring before plastering to ensure types of gypsum base plaster and adherence to job specifications finishing plaster. and good practice standards. m These products perform well Select from the suggested in appearance, structural ability, specifications that accompany Description General Uses sound isolation and fire endur- the description of each system. ance ratings, allowing architects to Conventional gypsum lath and Gypsum plaster systems are suitable PRODUCT SHELF LIFE plaster systems have long been for all interior plastering except design virtually any number of ceilings and partitions. Storage/ considered the industry standard areas directly exposed to free Product Shelf Life in wall construction. water or severe moisture. Lath Two-Way Hardwall 6 months and plaster is not recommended Performance Ideal for both residential and Gypsolite® Plaster 6 months commercial applications, lath and for exterior applications such as The relative performance of gypsum carports, soffits and open porches. and metal lath varies depending Gauging Plaster 3 months plaster systems provide smooth, Molding Plaster 3 months high quality wall surfaces, regardless Gypsum plasters are non-com- on the type of construction. When of framing alignment. bustible and act to prevent passage plaster on metal lath forms a mem- brane, as in a suspended ceiling or Lath and plaster deliver exceptional of intense heat from fire for extended periods. For specific fire resistance hollow partition, it’s more subject beauty and durability in interior to cracking than plaster on gypsum partitions and non-loadbearing ratings, see National Gypsum’s Gypsum Construction Guide. lath. On solid partitions, metal lath exterior walls. Conventional plaster is generally less subject to plaster systems are also commonly used cracking than gypsum lath. as the panel material for radiant heating systems in ceilings. When used with expanded metal lath, conventional plasters create a mechanical bond for maximum strength and durability. Gypsum plasters are also excellent for sculpting, casting decorative objects, and historic restoration.

3 Gypsum Plaster Base and Metal Lath

Kal-Kore® Plaster Base Metal Lath Products* DIAMOND MESH LATH Used as a plaster base and rein- forcement on almost all types of walls and ceilings, over wood or steel framing, flat or curved surfaces.

SELF-FURRING DIAMOND MESH LATH Used extensively in work, as a plaster reinforcement over interior masonry walls, and in steel column fireproofing. The self-furring dimples hold the metal lath 1/4" away from the surface to be plastered.

Description Technical Data 1/8" FLAT RIB LATH Kal-Kore® is a tapered edge gypsum Kal-Kore is available in two basic Designed to meet the demand for wallboard plastering base having a types: Regular and Fire-Shield Type rigid expanded metal lath used as blue absorptive face paper surface. X. Kal-Kore is 4' wide and is sup- a plaster base in all types of work. Although specifically designed as plied in 8’ through 16’ lengths. Widely used as reinforcement for a base for veneer plaster, it also Thicknesses are as follows: basecoat in ceramic tile work. provides an excellent base for con- Regular: 3/8" and 1/2". ventional basecoat plasters such as Gypsolite or Two-Way Hardwall. Fire-Shield: 1/2" Fire-Shield C, 5/8" Fire-Shield, 5/8" Fire-Shield C, produced to meet ASTM C 588/ C 1396. 3/8” RIB LATH Note: Installation of gypsum lath The 3/8" rib lath is used for ceilings and metal lath shall be in accor- under steel joist construction and dance with ASTM C 841. Do not metal reinforced concrete floors. It use 3/8" Kal-Kore Plaster Base with is also recommended for concrete conventional basecoat plasters. slab floors over steel joists.

* Metal products are not manufactured by National Gypsum Company. 4 Conventional Plaster Accessories*

DOUBLE V EXPANSION JOINT BULL NOSE CORNERBEAD Minimizes cracking in large plaster Reinforces exterior corners where areas. Also provides ground to rounded edges are required. Nose assure proper plaster or stucco 3/4" radius. Galvanized steel. thickness.

DOUBLE V CORNER WIDE FLANGE EXPANDED EXPANSION JOINT CORNERBEAD Similar in design to Double V Has 3-3/16" expanded flanges expansion joint but preformed to for use on masonry, beams and for fit corner angles. Galvanized steel column fireproofing. Galvanized or zinc. steel.

EXPANSION JOINT L RUNNER Designed to relieve stresses in Perforated – Ceiling or floor large gypsum and portland cement support for 2" solid lath plaster areas. Material will expand and plaster partition. and contract to allow for 1/8" Plain – Ceiling support for 2" to 5/8" opening. Incorporates a solid wallboard partition using 1" weather resistant joint. Galvanized shaftliner. steel or zinc.

EXPANDED FLANGE COLD ROLLED STEEL SQUARE CASING CHANNEL Has short, 90 degree return at plaster Used as studs for attaching metal surface, serving as a plastering stop. lath in 2" solid partitions. For furring or runners in suspended ceilings.

EXPANDED CORNERBEAD BEAM FURRING CLIP The 2-1/2" expanded flange ends Used to attach lath to flanges of 1/4" from the nose of the bead steel beams, joists and columns. providing reinforcement where Tempered spring steel. needed most.

* Metal products are not manufactured by National Gypsum Company. 5 Basecoat Plasters

Gold Bond ® BRAND Gold Bond ® BRAND Two-Way Hardwall Gypsum Plaster Gypsolite® Plaster Description Description Gold Bond® Two-Way Hardwall Gold Bond® Gypsolite® is a light- Plaster is a basecoat plaster which weight gypsum basecoat plaster requires the job site addition of an mixed at the mill with correctly aggregate and water to provide sized and proportioned perlite working qualities and is designed aggregate, requiring only the for interior use over all accepted Strength addition of water on the job. It High Insulating Value plaster bases. It may be applied by Two-Way Hardwall Plaster properly is manufactured to be trowel- Gypsolite has a “k” factor of 1.5 hand or used through pump/ spray proportioned with aggregate forms applied over gypsum plaster base, which provides about 3-1/2 times the plastering machines. a hard, durable base for the finish and in some cases metal lath insulating value of sanded plaster. (see LIMITATIONS.) Features/Benefits coat. Its high tensile and compres- Fire Resistance sive strength results in increased Gypsolite has excellent fire-resistive Controlled Uniformity Features/Benefits resistance to minor structural qualities and generally provides fire Two-Way Hardwall Plaster is set- Uniform Strength and movements, impacts and abrasions. ratings higher than sanded plaster. stabilized and adjusted for market Hardness Fire Resistance requirements and seasonal changes. Uniformity is assured through exact Two-Way Hardwall Plaster is Limitations When mixed with sand or other proportioning and thorough mixing essentially mineral in composition aggregate it has uniform working of graded perlite and gypsum plas- When used over metal lath, a sand and will not support combustion. qualities and excellent spread. ter at the mill. Gypsolite provides a float finish should be specified. A uniform base for the finish coat. smooth-trowel finish is not recom- mended since the combination of a Technical Data Lightweight relatively soft (perlite aggregated) Gypsolite weighs less than half AGGREGATE PROPORTION AND ESTIMATED COVERAGE basecoat and a hard (smooth- as much as sanded gypsum plas- trowel lime/gauging) finish has the Coverage, Sq. Ft. Thick- ter, thus reducing the dead-load Aggregate Sq. Yds. /Ton (Sq. M.) ness potential for cracking and spalling Proportions Plaster Base (Sq. M./Metric Ton) per Bag In. (mm) on framing. of the finish coat. Sanded Gypsum Lath 88-110 40-50 7/16" 1:2-1/2 (80-102) (3-5) (11.1) Sanded Gypsum Foil 88-110 40-50 7/16" Technical Data 1:2-1/2 Back Lath (80-102) (3-5) (11.1) GYPSOLITE ESTIMATED COVERAGE (50 LB. BAG) Sanded Metal Lath 45-63 20-26 9/16"* Coverage, Sq. Ft. Thickness 1:2-1/2 (42-58) (1.5-2.5) (14.3)* Sq. Yds. per Ton (Sq. M.) In. Sanded Brick & Clay Tile 88-110 40-50 9/16" Plaster Base (Sq. M/Metric Ton) per Bag (mm) 1:3 Concrete Block (80-102) (3-5) (14.3) Gypsum Lath and 90-100 32-35 7/16" Gypsum Foil Back Lath (83-92) (3-3.5) (11.1) *Measured from face of lath. Note: Sanded 1:2-1/2 means 1 part plaster to 2-1/2 parts sand by weight. Metal Lath 42-52 16-19 9/16"* (39-48) (1.5-1.8) (14.3)* WEIGHT COMPARISON OF BASECOAT PLASTERS *Measured from face of lath. Dry Set Mortar Weight Sanded 1:3 Gypsolite Weight lbs. per cu. ft. (kg/m3) 120 (1922) 50 (801) Specification Reference ASTM Designation C 28, Lbs./yd.2 (kg/m2) 3/8" (9.5 mm) thick 34 (18) 14 (8) Lbs./yd.2 (kg/m2) 1/2" (12.7 mm) thick 45 (24) 19 (10) “Gypsum Plasters”. Lbs./yd.2 (kg/m2) 5/8" (15.9 mm) thick 56 (30) 24 (13) Lbs./yd.2 (kg/m2) 3/4" (19.0 mm) thick 67 (36) 29 (16) Bag Weight Wet Mortar Weight 50 lbs. (22.7 kg) 25 lbs. (11.3 kg) Weight lbs. per cu. ft. (kg/m3) 140 (2243) 69 (1105)

Specification Reference ASTM Designation C 28, “Gypsum Plasters”. Bag Weight 50 lbs. (22.7 kg)

6 Finish Plasters

PHYSICAL PROPERTIES OF BASECOAT PLASTERS (TYPICAL TEST RESULTS PER ASTM C 472) Plaster Gypsolite Two-Way Hardwall to Two-Way Hardwall Two-Way Hardwall Properties Regular Sand by Weight and Vermiculite and Perlite Regular Masonry Regular Masonry Mix Mill Mix 1:1 1:2 1:3 100 lbs. (45.4 kg) 100 lbs. (45.4 kg) 100 lbs. (45.4 kg) 100 lbs. (45.4 kg) 2 cu. ft. (.06 m3) 3 cu. ft. (.08 m3) 2 cu. ft. (.06 m3) 3 cu. ft. (.08 m3) Approximate Compressive 900 1600 1150 750 500 300 900 650 Strength lbs. per sq. in. (kPa) (6201) (11024) (7923) (5168) (3445) (2067) (6201) (4479) Approximate Tensile 160 250 190 120 130 90 160 100 Strength lbs. per sq. in. (kPa) (1102) (1722) (1309) (827) (896) (620) (1102) (689)

Gold Bond® BRAND Gold Bond® BRAND Gypsum Gauging Plaster (Super White) Gypsum Moulding Plaster (Super White) Gold Bond Gauging Plaster, quick set Gold Bond Moulding Plaster is a very or slow set type, is designed for use white, finely ground gypsum, primar- with finish lime. It is specially ground, ily used for all kinds of ornamental calcined gypsum, which readily mixes plaster work. Because of its low with water and lime putty. Proper expansion, excellent strength and proportioning is essential, since hardness, it is specially adaptable for gauging adds strength and hardness casting in rubber, gelatin and other to the finish surface by reinforcing plaster basecoat. Smooth finish plas- types of moulds. For casting pur- Specification Reference the plastic non-setting lime against ters should be applied at a thickness poses, only water is added. For run- Complies with ASTM Designation shrinkage and cracking. A finish coat of not more than 1/16". Texture in-place ornamental work, such as C 59. of gypsum gauging plaster and finish finishes should be applied at a thick- cornices, the moulding plaster is used Note: Application of plaster shall lime, job mixed 2 parts hydrated ness of not more than 1/8". with lime putty, mixed 2 parts lime to be in accordance with ASTM C 842. lime to 1 part plaster by weight, is Specification Reference 1 part moulding plaster by weight. designed primarily for interior smooth Complies with ASTM Designation trowel application over a gypsum C 28. Technical Data GYPSUM MOULDING PLASTER Technical Data Method of Application Coverage* GYPSUM GAUGING PLASTER Trowel Finish 1000-1400 sq. yds./Ton (921-1290 m2/Metric Ton) Method of Application Coverage* 113-158 sq. ft./Bag (10.5-15 m2/bag) Trowel Finish 1000-1400 sq. yds./Ton (921-1290 m2/Metric Ton) *Based on one part plaster to two parts hydrated lime. 113-158 sq. ft./Bag (10.5-15 m2/bag) *Based on one part plaster to two parts hydrated lime. Bag Weight 50 lbs. (22.7 kg) Bag Weight Quick Set: 50 lbs. (22.7 kg) Slow Set: 50 lbs. (22.7 kg)

Mill-Mixed Finish Plasters For a mill-mixed finish plaster, use Extended Set Veneer Plaster. Kal-Kote Smooth Finish, Kal-Kote Requires the addition of water Texture Finish Plaster, Uni-Kal only. See page 17. Veneer Plaster or X-KALibur MILL-MIXED FINISH PLASTERS* Method of Product Application Coverage* Kal-Kote Smooth Finish Trowel 650-750 sq. yds./Ton (598-645 m2/Metric Ton) Kal-Kote Texture Finish Trowel 650-750 sq. yds./Ton (598-645 m2/Metric Ton) Uni-Kal and X-KALibur Trowel 600-665 sq. yds./Ton (553-613 m2/Metric Ton) *See page 17 for additional information.

77 Lath & Plaster Problems and Solutions

Conditions/Causes/ m Cracks* The cause(s) of these generally are m Environmental job conditions Prevention/Correction m Surface defects, blemishes, stains the result of: m Poor or improper plastering m m Conditions relating to plaster set practices and workmanship Plaster problems are rarely caused by Weak or soft plaster m Poor quality or incorrect propor- a gypsum plaster product deficiency. m Bond failure *Conventional plaster, although not con- tioning of aggregate In general, most conventional plaster m Finish coat problems sidered to be a structural member, is not m Structural movement delicate construction and can endure con- construction problems can be m Working qualities and setting siderable abuse without cracking. However, m classified into one of the following action Improper mixing, application or cracks can occur when excessive external categories. thickness of basecoat or finis forces caused by structural or component m Painting plaster movement over which the plaster is applied m Incorrect or improper lathing or are transmitted to the plaster or by extreme substrate environmental changes. m Dirty mixing equipment

Condition Construction Probable Cause Preventive Action Corrective Action CRACKS Connected Vertical Plaster applied over 1. Plaster too thin. Properly install lath, use 1. Apply another coat of And Horizontal Cracks gypsum or metal lath. 2. Weak plaster (too much properly sized and propor- plaster to proper thickness. Occurring At Somewhat or improper aggregate.) tioned aggregate and apply 2. Remove defective plaster Regular Intervals, 3. Lath improperly applied. plaster to the required work and replace with Usually In A Stepped thickness. properly proportioned Or Grid Pattern plaster. 3. Check Lathing Specifica- tions, remove and reapply lath properly and replaster.

Cracks Around And Plaster over masonry, cement 1. Poor construction of lintel, Follow proper construction 1. Patch cracked areas. Over Openings Such As block, gypsum tile or gypsum, door bucks improperly installation practices. 2. Apply coat of plaster to Doors Or Windows wood or other sheet lath. constructed or installed. proper thickness. 2. Plaster too thin. 3. Remove plaster and provide 3. Failure to use reinforcing. expanded metal rein- 4. Expansion of wood or forcement and replaster. metal framing. 4. Remove plaster, provide 5. Weak plaster, too much control joints, replaster. aggregate. 5. No correction – remove and replaster.

Fine Cracks Occurring 1. Basecoat over masonry, 1. Basecoat too rich, Follow proper plastering 1. Remove plaster and redo In A Random Pattern cement block, etc. insufficient aggregate. practices. properly. Usually Less Than 2. Lime putty finish over 2. Basecoat too dry when 2. Prepare basecoat by spraying 6" Apart. Shrinkage gypsum basecoat. finish applied – excessive with water to decrease suction. Cracks, Crazing, suction. 3. Strip finish, replaster with Alligatoring, Chip 3. Insufficient or slowset proper gauging. Cracks gauged finish. 4. Strip finish and correctly 4. Finish applied too thick. refinish. 5. Insufficient troweling of 5. Strip finish and tightly scratch, finish. apply 1/32" - 1/16" thick.

Random Cracks In Wall Plaster over any substrate. Structural movement. Use a properly designed Repair cracks. Or Ceiling, Generally and installed construction Large Cracks: Remove Running Full Length such as a suspended or plaster about 6” on each side Of Wall Or Width Of floating plaster system. of the crack down to the sub- Ceiling. May Adjoin strate. Place a strip of metal Other Cracks And lath in the cleared area, wet Are Generally Widely with water and replaster. Spaced Small Cracks: Open the crack slightly, wet and fill flush with a setting type joint compound.

8 Condition Construction Probable Cause Preventive Action Corrective Action CRACKS (cont.) Cracks At Wall Or 1. Plaster over gypsum lath. 1. a. Thin plaster. 1. a. Be sure proper plaster- 1. a. Apply second coat of Ceiling Angles 2. Plaster over masonry. b. Failure to use expanded ing grounds are in place. plaster to proper thickness. metal reinforcement. b. Always apply expanded b. Cut out plaster and c. Structural movement. metal reinforcement in all patch. 2. Failure to tie walls interior angles. c. Patch cracks. together. c. Follow proper construc- 2. Patch cracks. tion practices. 2. Follow proper construction practices.

Cracks Not Due To 1. Plaster over metal or 1. a. Metal lath too light. Follow proper construction 1. a/b. Remove lath and Any Of The Previously gypsum lath. b. Metal lath not lapped practices. plaster, apply proper Mentioned Causes And 2. Plaster over metal or or properly tied. weight lath and replaster. Are Not The Result Of gypsum lath on steel c. Thermal shock. c. Patch cracks. Structural Movement framing. 2. a. Improper spacing of 2. a. Remove plaster, properly framing members. space framing and replaster. b. Thermal shock. b. Patch plaster. SURFACE DEFECTS Fuzz (Efflorescence) On Basecoat or finish coat over Efflorescence – water soluble Fur wall away from the Eliminate the source of Surface, White Or Colored, masonry or concrete substrate. salts are deposited on the masonry or concrete prior to moisture. Is Water Soluble And Can surface of the plaster as the plastering. Be Removed By Brushing masonry or concrete dries.

Streaky Discoloration Lime putty finishes gauged 1. Use of too much water 1. Use proper amount 1–3. Paint plastered surfaces with gauging plaster or while troweling. of water while troweling. with a good quality paint Keene’s cement. 2. Improperly/poorly mixed 2. Thoroughly mix the lime as recommended by the lime and gauging material. and gauging. paint manufacturer. 3. Dirty tools, water, or mixing 3. Use only clean tools, mixing 4. See correction for FUZZY equipment. equipment and water. surface. 4. Efflorescence. 4. See prevention for FUZZY surface.

Streaked Finish, Joinings Finish plaster over any 1. Too much water used Use only the proper amount Prime and paint surface Showing, Dirty Areas substrate. while troweling. of clean water during trow- with a good quality paint as 2. Use of dirty water during eling. recommended by the paint troweling. manufacturer.

Blisters On Finish Coat Gauged lime putty or mill 1. Basecoat too green (wet). 1/2. Allow basecoat to dry Remove blistered finish and (Entrapped air between mixed gypsum plaster trowel 2. Insufficient suction. sufficiently to develop replaster. finish and substrate) finishes. 3. Too much water used proper suction. while troweling. 3. Dash water on surface 4. Insufficient gauging. sparingly during troweling. 5. Troweling before suf- 4. Use proper proportions of ficient take-up. lime putty and gauging. 5. Allow plaster to take-up sufficiently before troweling.

Projections On Surface Finish or basecoat plasters Unslaked lime or foreign Use Type S hydrated lime or Remove the core of the Which Fall Out Leaving containing lime. matter in the plaster which properly soak lime to insure crater or pits and patch Craters Or Pits. May Have hydrates and expands after proper hydration. with finish plaster or ready Fine Cracks Radiating application. mix joint compound. From The Center

9 Condition Construction Probable Cause Preventive Action Corrective Action WEAK OR SOFT PLASTER Soft, White, Chalky Basecoat over any Usually occurring during Screen openings to minimize Spray dried out areas with Surface plaster base. dry, hot weather. Too much drafts during dry, hot weather water or a solution of alum ventilation has removed water and spray the surfaces and (1 lb. alum per 3 gallons of from the plaster before it floors with water during the water). has set. Called “dry-out”. setting period.

Soft, Dark, Damp Basecoat over any 1. DAMP WEATHER - too 1. Maintain proper heating 1. Dry plaster by ventilating Plaster Surface substrate. little ventilation during and ventilating prior to, and heating. If condition damp weather, water during and after plastering. has existed for too long remaining in plaster 2. Maintain minimum 55˚F it cannot be corrected. too long after set has prior to, during and after Plaster must be removed occurred, “Sweat-Out”. plastering and provide and replastered. 2. FREEZING WEATHER adequate ventilation until 2. Close building, heat CONDITIONS – FROZEN plaster is dry. building until plaster sets PLASTER and continue heating and ventilating after set.

Weak, Soft Plaster, Gypsum basecoat over any 1. Too fine or poor aggre- Use only aggregate meeting No correction – remove the Due To Improperly plaster base. gate grade. ASTM specification. Properly plaster and replaster. Proportioned Aggregate 2. Too much aggregate. proportion aggregate and plaster. BOND FAILURE OF BASECOAT Separation Of Basecoat Basecoat over gypsum lath. 1. Too much or improper 1. Use only proper and No correction – remove the From Gypsum Lath aggregate used. ASTM-specified plaster/ plaster and replaster. 2. Frozen plaster. aggregate proportions. 2. Maintain a minimum temper- ature of 55˚F in the building prior to, during and after application and provide adequate ventilation.

Separation Of Basecoat Basecoat over metal lath. 1. Too much or improper 1. Use only proper and No correction – remove the From Metal Lath aggregate. ASTM-specified plaster/ plaster and replaster. 2. Frozen plaster. aggregate proportions. 3. Scratch coat too thin. 2. Maintain a minimum temperature of 55˚F in the building prior to, during and after application and pro- vide adequate ventilation.

Separation Of Basecoat Basecoat over unit masonry. 1. Excessive suction of the 1. Dampen the masonry to No correction – remove the From Unit Masonry masonry base. reduce suction. plaster and replaster. 2. Masonry base has a 2. Roughen the masonry non-absorbent or glazed surface to provide a key surface. for the plaster. 3. Efflorescence present on 3. Eliminate the source of the masonry base. moisture causing the efflo- rescence. Fur away from the masonry surface and apply lath over the furring.

10 Condition Construction Probable Cause Preventive Action Corrective Action BOND FAILURE OF BASECOAT (cont.) Separation Of Gypsum Basecoat over monolithic Concrete bonding agent not Apply plaster bonding agent No correction – remove the Plaster From Monolithic concrete. applied. per ASTM specification – plaster and replaster. Concrete Surface before application of plaster.

Brown Coat Plaster Three-coat plaster work. 1. Weak scratch coat plaster. 1. See preventive actions No correction – remove the Separating From 2. Failure to provide adequate under weak, soft plaster. plaster and replaster. Scratch Coat Plaster mechanical keying to 2. Do not over trowel scratch scratch coat. coat; rake or broom scratch coat to provide mechanical keying. FINISH COAT PROBLEMS Gauged Lime Putty Gauged lime finish over 1. Brown coat too weak, 1. Make sure brown coat 1. No correction – remove Finish Coat Separating basecoat. too smooth, too wet (too is properly prepared to finish coat, correct condi- From Brown Coat Plaster little suction) or too dry receive finish. tion of brown coat and (too much suction). 2. Apply finish, taking pre- replaster. 2. Finish applied improperly. cautions to follow recom- 2/3. No correction – remove 3. Incomplete hydration of mended practices. finish coat and replaster. finish lime. 3. Use only Type S hydrated lime and mix according to recommendations.

Gypsum Sand Float Or Gypsum sand finish over 1. Brown coat too weak. Make certain that the brown 1. No correction – remove Trowel Finish Separating basecoat. 2. Brown coat too dry. coat is sound, not overly dry finish, correct brown coat From Brown Coat 3. Brown coat too smooth. and has adequate roughness condition and replaster. to provide keying to the finish. 2. No correction – remove finish, spray brown coat with water to reduce suction and replaster. 3. No correction – remove finish, roughen brown coat to provide adequate keying and replaster.

Finish Coat Weak, Soft Gypsum finish over basecoat. 1. Insufficient gauging 1. Use proper proportions No correction – remove the plaster used. of gauging to lime putty. plaster and replaster. 2. Retempered finish coat. 2. Do not retemper plaster 3. Inadequate or insufficient that has started to set. troweling of the finish. 3. Lime putty finishes must be troweled sufficiently to densify the finish and develop proper strength.

Lime/Gauging Finish – Gauged lime finish over 1. Old material, warehoused 1. Use only fresh lime which There is no correction for Tough, Short Working basecoat. too long or improperly. has been properly ware- these occurrences. Or Lumpy Lime Putty 2. Lime improperly mixed or housed. soaked. 2. Mix and/or soak lime 3. Low temperatures. according to supplier’s recommendations. 3. Maintain proper temper- ature above 55˚F prior to, during and after plastering.

Set Not Uniform Gypsum finish over 1. Improper gauging plaster 1. Use either Quick or Slow There is no correction for basecoat. used. set gauging in the proper these occurrences. 2. Temperature conditions proportions. too hot or cold. 2. Maintain proper temper- ature above 55˚F prior to, during and after plastering. 11 Condition Construction Probable Cause Preventive Action Corrective Action FINISH COAT PROBLEMS (cont.) Finish Coat Gypsum finish over 1. Basecoat plaster too dry. Follow good plastering 1. Apply finish coat over Works Hard basecoat. 2. Finish coat mixed too practices. green base or spray the stiff. dry base lightly with water before finishing. 2. Use correct amount of water when mixing finish coat. WORKING QUALITIES AND SETTING ACTION Slow Plaster Sets – Basecoat plaster over any 1. Retarding action of Use only proper plaster 1/2. Obtain good sand Not Set After Five Or substrate. aggregate. aggregate, potable water and water or accelerate Six Hours 2. Retarding action of water and fresh plaster. mixes. being used. 3. Replace with fresh plaster 3. Old plaster set lengthened or accelerate mixes. due to aging.

Plaster Sets Too Quickly Basecoat plaster over any 1. Tools and mixing equip- Keep tools and mixing 1–3. Judiciously use retarder To Be Darbied Or Sets substrate. ment not free of set plaster. equipment clean, use only to slow setting, clean In Mortar Box Or On 2. Dirty or contaminated potable water and clean equipment and obtain The Board sand or water. sand for mixing. Use fresh clean water and sand. 3. Plaster too old or became plaster which has been 4. Reduce plaster mixing wet in storage or on the stored properly. Follow time. job site. good plastering practices. 4. Plaster being mixed too long.

Plaster Works Hard Or Basecoat plaster over any 1. Plaster is old or stored Use only fresh, properly 1. Blend equal parts of Short, Will Not Spread, substrate. under poor conditions. stored plaster. fresh and old plaster. Will Not Carry Proper 2. Too much or improper 2. Use proper aggregate at Amount Of Aggregate aggregate being used. proper proportions.

Painting Plaster Various job conditions such as suction differences, wet or only partially dry walls, and reactions between paint and lime may cause unsatisfactory paint finishes, particularly on new construction. Alkali-resistant primers specifically formulated for use over new plaster will permit decorating with oil or latex type paints. Quality paint products should be used and manufacturers’ recommendations followed. Finished plaster should be painted or covered to conceal possible discoloration. The paint system should be suitable for use over plaster surfaces that contain lime. It is essential that plaster be sound and completely dry before painting. Conventional plaster may require 30 to 60 days to fully dry.

12 Veneer Plaster 09 26 13/NGC

Two-Coat System m All are designed for trowel Features/Benefits application. Veneer Plasters (Kal-Kote®) are not suitable for conveyance m Kal-Kote System may be used or application by conventional for plaster-embedded electric plastering machines. radiant heating cable systems. m Compared to conventional m Same application techniques as plasters, Veneer Plaster Systems for conventional plaster. are more subject to beading (ridging) and cracking at the m Greater crack resistance than joints under rapid drying condi- one-coat systems. tions such as those caused by m Can be applied directly to low humidity, high temperature concrete block. and/or high draft exposure. m All provide a base over which Limitations paints or other finishes should m Not recommended for exterior be applied. use or where subject to weath- m Do not use a polyethylene ering, direct water contact or vapor retarder unless structure temperature exceeding 125˚F is ventilated adequately during (52˚C) for extended periods application of veneer plasters. of time. m A bonding agent must be m Framing spacing is limited and applied to monolithic concrete partition heights are reduced in prior to application of either Description Features/Benefits comparison with some standard system. Veneer Plaster Systems consist of The advantages of veneer plaster constructions. m Do not sand finished plaster. a 4' wide gypsum plastering base over other commonly used partition m Provides less rigidity than similar with a special, highly absorptive and ceiling systems include: standard plaster systems. paper surface that is covered with PRODUCT SHELF LIFE m Rapid installation which reduces m When Uni-Kal/X-KALibur will be thinly troweled, special purpose overall construction time. applied, do not install Kal-Kore Storage/ plasters. Two basic types of veneer Product Shelf Life too far in advance of plastering plaster are available: Uni-Kal and m Appearance and surface of X-KALibur 12 months since Uni-Kal/X-KALibur bond X-KALibur, which are one-coat conventional plaster at lower Kal-Kore Basecoat 12 months can be adversely affected if face plaster system products; and Kal-Kote, cost than regular plastering. of Kal-Kore has become faded Uni-Kal 12 months a two-coat plaster system. The m High resistance to cracking, from light. If Kal-Kore has been Kal-Kote Smooth 12 months gypsum plaster base, Kal-Kore, is nail-popping, impact and faded, apply Kal-Kote Base Kal-Kote Texture 12 months erected in the same manner for abrasion failure. Plaster or a plaster bonding both systems. Both veneer plaster m Mill-mixed plaster components agent to obtain good bond. systems can be specified for virtually help assure uniform installation all types of partition and ceiling performance and finished job constructions including wood or quality. steel framing or furring and masonry. For both residential and commercial One-Coat System buildings, either type of veneer Features/Benefits plaster system produces a wall more (Uni-Kal®/X-KALibur®) nail-pop resistant than m Requires only one plastering and, when properly installed, more material on the job. crack resistant than conventional m Slightly lower in-place cost than lath and plaster. two-coat system. m Can be applied directly to concrete block. m X-KALibur is formulated to have extended set characteristics beyond traditional Uni-Kal setting times.

13 Veneer Plaster System Components

SPECIFICATIONS Size Thickness Edge Pcs./Bdl. 4' x 8' 3/8" (9.5 mm) Tapered 2 (1219 mm x 2438 mm) 4' x 8', 12' 1/2" (12.7 mm) Tapered 2 (1219 mm x 2438 mm, 3657 mm) 1/2" (12.7 mm) FSK-C 4' x 8', 12' 5/8" (15.9 mm) Tapered 2 (1219 mm x 2438 mm, 3657 mm) FSK 4' x 8', 12' 5/8" (15.9 mm) Tapered 2 (1219 mm x 2438 mm, 3657 mm)

FASTENERS FOR ATTACHING KAL-KORE Framing Kal-Kore Fastener Fastener Spacing Screw 1/2" (12.7 mm) Type S Screws 12" o.c. Max. Studs & 1" (25.4 mm) for single layer (305 mm) Furring 5/8" (15.9 mm) 1-5/8" (41.3 mm) for two-ply 3/8" (9.5 mm) 1-1/4" (31.8 mm) annular Ceiling 7" o.c. or 4d box nails** (178 mm) Max. Wood 1/2" (12.7 mm) 1-1/4" (31.8 mm) annular Sidewall 8" o.c. Kal-Kore® Framing or 5d box nails** (203 mm) Max. 5/8" (15.9 mm) 1-3/8" (34.9 mm) annular Kal-Kore is a tapered edge gypsum or 6d box nails** wallboard plastering base having a ** Alternate: On walls, 1-1/4" (31.8 mm) Type W screws are spaced 12" (305 mm) when blue absorptive face paper surface framing is 24" o.c. (610 mm), 16" (406 mm) when framing is 16" o.c. (406 mm). designed to permit rapid trowel application and strong bond of SPACING OF FRAMING OR FURRING Kal-Kote, Uni-Kal and X-KALibur Type of Maximum plasters. Also available foil backed Framing or Kal-Kore Spacing or Fire-Shield (Type X). Kal-Kore is Furring Thickness on center manufactured to conform to ASTM Wood 3/8" (9.5 mm) 16" (406 mm)* 1/2" (12.7 mm) 24" (610 mm)** Specification C 588/C 1396 and 5/8" (15.9 mm) 24" (610 mm) CSA A82.27. Metal*** 3/8" (9.5 mm) N.A. 1/2" (12.7 mm) 16" (406 mm) 5/8" (15.9 mm) 24" (610 mm) N.A.–Not Approved. * Bound edge of Kal-Kore must be at right angles to framing for ceiling or walls. ** Bound edge of Kal-Kore must be at right angles to joists. 16" (406 mm) maximum spacing for bound edge of Kal-Kore parallel to joists. *** On ceilings, screw furring channel [7/8" (22.2 mm) depth] shall span 48" (1219 mm) maximum. Resilient furring channel [1/2" (12.7 mm) depth] shall span 24" (610 mm) maximum. For greater spans, 1-5/8" (41.3 mm) Screw Studs may be used as Ceiling Furring Channels provided they are secured with flanges up (open side up) at spans not to exceed: 6' (1829 mm) at 12" o.c. (305 mm) spacing, 5'6" (1676 mm) at 16" o.c. (406 mm) spacing and 5' (1524 mm) at 24" o.c. (610 mm) spacing.

14 Kal-Kote® Kal-Kote® Uni-Kal®/X-Kalibur® Base Plaster Smooth Finish Uni-Kal and X-KALibur are single Kal-Kote Base Plaster is a specially Kal-Kote Smooth Finish is designed component veneer plasters for designed high strength basecoat to provide a white smooth trowel application over Gold Bond tapered plaster for application 1/16" finish using conventional plastering edge 1/2" Regular or 5/8" Fire- minimum thickness over Kal-Kore, techniques. Apply not exceeding Shield Kal-Kore, or as a finish masonry or monolithic concrete 1/16" over Kal-Kote Base. coat over Kal-Kote base. When applied in a thin coat 3/32" thick that has been treated with a Requires the addition of water and troweled to a smooth finish, bonding agent. only. It may also be used as a finish they provide a durable, abrasion- Strength of Kal-Kote Base is sub- for conventional basecoat plasters. resistant surface for further stantially greater than that exhibited Small amounts of commercial decoration. X-KALibur has a by typical sanded basecoat plaster. retarder may be cautiously used to longer extended working time. slow the setting time when used Fire Resistance Uni-Kal and X-KALibur may be over conventional basecoat plasters. Fire ratings equivalent to those of worked to a variety of textured drywall systems can be obtained Bag Weight finishes. by applying the corresponding 50 lbs. (22.7 kg) Uni-Kal and X-KALibur applied not Kal-Kore type and thickness over Coverage (est.)* exceeding 1/16" may be used as the same framing member size and a finish coat over a 3/32" coat of 1/16" coat troweled on Kal-Kote spacing, with the same fasteners. Kal-Kote Base Plaster for a total Base Plaster, 650-700 sq. yds. per The total plaster thickness should minimum thickness of 1/8". be a minimum of 1/8". The minimum ton (145-160 sq. ft. per bag). Strength of Uni-Kal and X-KALibur 1/8" thickness is achieved by ® provides a surface resistant to applying a finish not exceeding Kal-Kote abrasion, cracking and nail-pops. 1/16" over 3/32" of Kal-Kote Texture Finish Base Plaster. Kal-Kote Texture Finish is designed Fire Resistance Specification Reference to provide a variety of decorative Fire ratings equivalent to those of surfaces using common plastering drywall systems can be obtained by ASTM Designation C 587. techniques. Applied as a 1/16" applying the corresponding Kal-Kore Bag Weight finish coat over Kal-Kote Base. It type and thickness over the same requires the addition of water only. 50 lbs. (22.7 kg) framing member size and spacing Bag Weight with the same fasteners and 3/32" Coverage (est.) of Uni-Kal or X-KALibur. 50 lbs. (22.7 kg) 1/16" on Kal-Kore Base, 425-475 Specification Reference sq. yds. per ton (93-106 sq. ft. Coverage (est.)* ASTM Designation C 587. per bag). One coat to level over 1/16" coat troweled on Kal-Kote masonry, 225-275 sq. yds. per ton Base Plaster, 650-700 sq. yds. per Bag Weight (50-63 sq. ft. per bag). ton (145-160 sq. ft. per bag). 50 lbs. (22.7 kg) Coverage (est.)* 3/32" on Kal-Kore Base, 600-665 sq. yds. per ton (135-150 sq. ft. per bag). One coat to level over masonry, 300-350 sq. yds. per ton (70-80 sq. ft. per bag).

*Coverage estimates over conventional plasters are approximately the same as over Kal-Kore Base Board for conventional plasters.

15 Veneer Plaster Accessories* Used in Both One-Coat and Two-Coat Systems

VENEER CORNERBEAD E-Z STRIP® CONTROL JOINT Formed of galvanized steel to protect Designed for drywall or veneer exterior corners with veneer plas- plaster systems. A vinyl extrusion tering. Flange length 1-1/4". used as an expansion or control joint for ceilings or partitions.

EXPANDED VENEER KAL-MESH TAPE CORNERBEAD A coated non-adhesive fiberglass Used as an alternate to the Kal- tape which is stapled to Kal-Kore Korner Bead for exterior corners. to reinforce all joints and interior Has 1-1/4" flanges. angles.

ARCH CORNERBEAD 1-1/2" DRYWALL FURRING Can be used straight for exterior CHANNEL CLIP corners or flanges, or may be Attaches screw furring channel to snipped and bent to form arches. 1-1/2" cold rolled steel channel.

ENEER J TRIM CASING BEAD .093 ZINC CONTROL JOINT Used as a finished edge at door Designed as an expansion or and window jambs by slipping over control joint for ceiling and edge of plaster base. partition areas for both drywall or veneer plaster systems.

VENEER L TRIM CASING BEAD Used as a finished edge at door and window jambs.

* Metal products are not manufactured by National Gypsum Company.

16 Recommendations

Veneer Plaster fasteners through channel flanges control joints are created using E-Z Three acceptable methods of for Metal into the masonry or concrete. Strip Control Joints. treating Kal-Kore joints are: and Wood Framing Fasteners shall be spaced on 4. Fasten Kal-Kore to framing Drywall Paper Tape alternate flanges not over 24" o.c. members with face out, using the Treatment Method 1. Wood Studs or Joists. Wood Apply Kal-Kore vertically or members shall meet the minimum proper type and spacing of fasten- 1. Trowel Kal-Kote Base Plaster, horizontally in maximum lengths ers shown under types of fasteners. requirements of local building codes. to minimize end joints. Uni-Kal or X-KALibur over joint line Framing shall not exceed spacing 5. Draw Kal-Kore tight to framing. filling the channel formed by the shown on page 14. Most partition 4. Furred Ceilings with Bar Joists. Drive fasteners straight and dimple tapered edges of the Kal-Kore board fire ratings require that Kal-Kore be Attach regular furring channel 16" o.c. the surface without breaking the in an even fashion. applied vertically. When such ratings to bar joists spaced up to 4' o.c. paper face. Resilient Furring Channel (wire-tied 2. Center drywall paper tape over are not required, horizontal applica- Veneer Cornerbead the joint line and embed the tape tion may be used to minimize joints. only) shall span a maximum of 24". Wire tie Furring Channel to joists or Application into the soft plaster using a trowel For ceilings, application at right and level the joint. Tape the full angles to framing is preferred. use 1-1/2" Drywall Furring Channel Install Veneer Cornerbead using appro- Clip for 1-1/2" carrying channel. Apply priate fasteners spaced 12" apart. length of the joint. 2. Metal Studs. Align floor and Kal-Kore with paper bound edges at E-Z Strip Control Joint 3. Allow the treated joints to set ceiling tracks to assure plumb parti- right angles to the furring channel. prior to general plaster application. tion. Secure track with appropriate Application fasteners at a maximum of 24" o.c. Kal-Kore Application Install E-Z Strip Control Joint at 30' Sta-Smooth Paper Tape Treatment Method Position studs in track on specified Note: Application shall conform to max. spacing on walls and 50' max. ® BRAND TM centers by rotating into place for a ASTM C 844. spacing in either direction on ceilings. 1. Mix ProForm Quick Set friction fit. Secure studs located adja- Apply the control joint with staples Setting Compound per instructions cent to door and window frames, 1. Cut and position Kal-Kore accu- spaced 6" along each side of the on package. Do not contaminate partition intersections and corners rately. Bring all joint edges together flanges. the compound with other materi- but do not force into place. Position by self-drilling sheet metal screws Treatment of Kal-Kore Joints als, dirty water or previous mixes. through both flanges of studs and all end joints over framing members. Do not retemper. To avoid ridging, minimize gaps Pre-treat all joints and fasteners in tracks or by use of screw stud clinch- ® BRAND between adjacent panels. Kal-Kote and Uni-Kal Plaster Systems 2. Apply the ProForm Quick ing tool. Apply Kal-Kore vertically for SetTM Setting Compound to the joint most fire ratings. When ratings are 2. Minimize the number of end with Kal-Kote Base Plaster, Uni-Kal, ® BRAND by hand or machine tool. The dry- not required, horizontal application joints by using maximum practical X-KALibur or ProForm Quick SetTM Setting Compound. wall paper tape must be centered may be used to minimize joints. lengths with proper positioning. over the joint line and embedded 3. Masonry Wall Furring with 3. Stagger joints so that they occur Low humidity, high temperatures into the soft compound. Do not Screw Furring Channel. Attach on different framing members and and rapidly circulating air can over-trowel to a slick surface. furring channel vertically spaced will not be directly opposite one cause cracking of plaster and joint Leave the surface rough to provide not to exceed spacing shown on another on partitions. Avoid joining beading when Kal-Kore is applied mechanical keying of the plaster. to metal framing. To minimize this page 14. Fasten each channel with Kal-Kore at corners of doors, window 3. Allow the treated joints to set concrete stub nails or appropriate frames, and other openings, unless during these conditions, joints may be pre-treated using paper tape. and dry prior to general plastering.

Uni-Kal or X-KALibur Finish Kal-Kote Smooth Finish Kal-Kote Texture Finish

Kal-Kote Base Kal-Kote Base

Kal-Kore Board Kal-Kore Board Kal-Kore Board

17 Kal-Mesh Treatment Method Do not use self-adhering mesh. 1. Center and secure Kal-Mesh over all joints and interior angles with 1/4" or 5/16" staples. 2. Position staples a maximum of 24" apart as follows: A. Joints: at alternate edges for the run from end to end and directly opposite one another at either end. B. Angles: along ceiling edge only for wall-to-ceiling angles. Along one edge for wall-to-wall angles. 3. After the first staples are placed at the end of a joint or angle, pull unstapled Kal-Mesh as stapling proceeds to assure that it will lie flat against the Kal-Kore. 4. Pre-treat all joints and Kal-Beads with Kal-Kote, Uni-Kal or X-KALibur Plaster. Tightly trowel over joint line in both directions to prevent voids, feathering to a maximum during and after installations. 2. Add plaster and allow to soak directly, or in previously prepared width of about 6". During cold weather, maintain a for about 1 minute or add plaster water solution form to obtain the temperature 55˚F (13˚C) to 70˚F as mixer is turning, then mix until most uniform effect. 5. Allow the treated joints to set (21˚C) before, during and after uniformly wetted. prior to general plaster application. 2. Never use gauging or moulding installation of all system components 3. Add remaining water and mix plasters in place of commercial Plastering until building is occupied. sufficiently to obtain desired lump- accelerator since they can adversely Mixing free material fluidity. affect working qualities. Note: Application shall conform to ASTM C 843. Equipment: Mixing should be Note: Kal-Kote Application done with a high-speed mechanical A. Mixing periods greater than The same general job conditions mixer. A paddle-type agitator fitted 5 minutes will not be required if Over Kal-Kore used in good conventional plaster- to a 500-600 RPM heavy duty, proper equipment and procedure Basecoat Over Kal-Kore ing practice should be maintained. 1/2" electric drill and a clean, are used. However, because Veneer Plaster 1. Tightly scratch material into smooth-sided drum of convenient coats are thin, particular action B. Mix no more than two bags per previously treated joints and corner- size are recommended for rapid, must be taken to guard against batch to avoid mixing too far in beads, then immediately scratch-in efficient mixing of all Kal-Kote dryouts (primarily avoiding direct advance of application. tightly over the wall and/or ceiling Plaster types. area. exposure to concentrated sources C. Caution is advised against mixing of heat and drafts.) Water Ratios: Use only clean, more than two successive batches 2. Double back over the area just fresh water suitable for human Special attention should also be without thorough equipment clean- troweled with material from the consumption. Basecoat: 6-8 qts. given to temperature conditions up to avoid undue set acceleration. same batch bringing total thickness per 50 lb. bag. Smooth Finish: under which the system is installed. up to 1/16" minimum. 18-20 qts. per 50 lb. bag. Texture D. Avoid the practice of mixing Both “in-place” and application Finish: 11-12 qts. per 50 lb. bag. partial bags since this leads to 3. When plaster has “taken up,” performance of individual Veneer Uni-Kal and X-KALibur: 13-15 qts. difficulty in maintaining uniform eliminate excessive trowel marks System components will be greatly per 50 lb. bag. material qualities. and fill all surface voids and imper- enhanced if all construction areas fections to obtain a reasonably Job Setting Adjustment and materials are at a suitable Procedure uniform surface. Do not over-trowel temperature equilibrium before, 1. Put all but 1 to 2 qts. of the 1. Basecoat and Finish Plasters: to a slick surface. Roughen the proper water volume in a suitable Small amounts of commercial unset basecoat plaster surface with mixing drum. retarder or commercial gypsum a serrated darby or lightly wire rake type accelerator may be cautiously to provide mechanical keying for Note: Starting with an insufficient used to adjust setting time when the finish plaster when necessary. amount of mixing water will seriously extreme conditions demand. When degrade mixing and application commercial retarder or accelerator performance. is used, add to mixing water

18 Smooth Finish Over Basecoat 2. Double back over the area just Veneer Plasters Direct 3. When plaster has “taken up”, 1. Apply only over properly pre- troweled with material from the to Bond-Coated eliminate excessive trowel marks pared Kal-Kote basecoat plaster. same batch bringing total thickness Monolithic Concrete and fill all surface voids and imper- Scratch-in tightly, then double back up to 3/32" minimum. fections to obtain a reasonably Description with material from the same batch 3. Begin finish troweling at time uniform surface. Do not trowel to immediately to create a uniform of initial set, using water sparingly. The Kal-Kote System, consisting of a slick surface. Roughen the unset coat not exceeding 1/16" in average Final troweling must be accom- a basecoat plaster and a finish coat basecoat plaster surface with a thickness. plished before complete set takes plaster, Uni-Kal or X-KALibur may serrated darby or lightly wire rake be applied directly to monolithic to provide mechanical keying for 2. Remove trowel marks, “cat faces,” place, as evidenced by darkening concrete treated with a bonding the finish plaster when necessary. and other major surface imperfec- of the surface. agent. tions by “drawing-up” or “laying Note: Uni-Kal or X-KALibur may Smooth or Textured Finishes down” the surface with light trowel be applied to produce a textured Limitations Apply finishes to the Kal-Kote pressure when plaster has stiffened. finish. 1. Surface to be plastered shall Plaster as outlined under the regular Use water sparingly if needed, but A. When Uni-Kal or X-KALibur is be treated with a bonding agent Kal-Kote System as described on do not over-trowel or over-water mixed, add up to but not exceed- applied according to manufacturer’s page 18. because this aggravates any normal ing 50 lbs. of silica sand, texturing directions. The performance of this Uni-Kal or X-KALibur tendency for blistering when working grade, per 50 lb. bag of plaster. system is the sole responsibility of over low suction bases. Such the bonding agent manufacturer. Application over B. The sanded Uni-Kal or X-KALibur Bonding Agent blistering will be eliminated by the mix should be scratched-in tightly 2. Concrete should be aged at final water-troweling operations. over the plastering base. Immediately least one month prior to plastering. 1. First straighten any major surface irregularities such as holes, ridges, 3. Water-trowel to densify and polish double back over the area just 3. Kal-Kote Smooth or Texture wavy sections, etc. Scratch plaster the surface to the desired degree troweled with material from the Finishes are not designed for direct in tightly by trowel and fill out to when plaster has set, eliminating same batch. application to concrete, but must any adjacent level area. any blistering if present. Never use C. When plaster is well taken up, first have Kal-Kote Base Plaster a felt “blister brush” as a substitute float to the desired texture finish. applied to fill and level surface. 2. Allow the straightening material for water troweling! to set. Painting Plaster 4. Do not apply system to the 4. Uni-Kal and X-KALibur Plaster interior side of exterior walls below 3. Tightly scratch material in over may be substituted for Kal-Kote Various job conditions such as grade. To use above grade these the wall and/or ceiling area. This Smooth Finish. suction differences, wet or only walls shall be kept dry and shall application should be about 1/16" partially dry walls, and reactions Texture Finish Over Basecoat have been properly waterproofed thick. Double back over the area between paint and lime may on the exterior side to prevent just troweled with material from 1. Apply per (1) under Smooth cause unsatisfactory paint finishes water penetration. the same batch bringing total Finish. particularly on new construction. thickness up to 3/32" minimum. Application Procedures 2. When plaster has stiffened, float Alkali-resistant primers specifically 4. Begin finish troweling at time Note: Application shall conform to its surface to any desired finish. formulated for use over new plaster of initial set, using water sparingly. ASTM C 843. Do not float the soft surface will permit decorating with oil or Final troweling must be accom- of plaster which has already set. latex type paints. Quality paint plished before complete set takes products should be used and Kal-Kote Base Up to equal parts of clean, graded Application Over place, as evidenced by darkening manufacturers’ recommendations of the surface. silica sand may be added to Uni- followed. Finished plaster should Bonding Agent Kal and X-KALibur to aid texturing. be painted or covered to conceal 1. First straighten any major sur- Veneer Plasters Direct Uni-Kal or X-KALibur possible discoloration. The paint face irregularities, such as holes, to Unit Masonry system should be suitable for ridges, wavy sections, etc. Scratch Application Description use over plaster surfaces that plaster in tightly by trowel and fill over Kal-Kore contain lime. out to any adjacent level area. The Kal-Kote System, consisting of a basecoat plaster and a finish 1. Tightly scratch material into It is essential that plaster be sound 2. After the straightening material coat plaster, Uni-Kal or X-KALibur, previously treated joints and corner- and completely dry before paint- has set, trowel in a tight scratch and the one-coat system, may be beads, then immediately scratch-in ing. Under good drying conditions, coat over the entire area to be applied direct to masonry surfaces tightly over the wall and/or ceiling veneer plaster may be painted 48 plastered; then immediately double providing the following recommen- area. hours after application. back with material from the same dations are followed. batch to minimum thickness of 1/16" or as required to achieve a level surface. Use a rod or feather edge if needed.

19 Recommendations Veneer Systems Application Procedures 2. Apply Kal-Kore to the flanges of 1. Surface must be free from dirt, Applied to Masonry 1. Begin application of Z Furring Z Channel with 1" Type S screws grease, oil, mold, parting agents, with Z Furring members by positioning first channel spaced 12" o.c. Normally, vertical or any material which will prevent Channel System vertically at a corner, locating it on application of Kal-Kore is recom- plaster adhesion. the wall adjacent to the wall being mended; however, for installations Description 8' or less in height, horizontal 2. When erecting masonry, insulated first. This system consists of a Z Furring application may be preferred since strike joints flush. If masonry has The insulation thickness determines Channel, rigid insulation and the number of joints would be recessed joints, fill joints flush to the distance of Z Furring web from the components of the Kal-Kote reduced. masonry surface with basecoat wall being insulated. At the appro- and Uni-Kal or X-KALibur Veneer plaster, Uni-Kal or X-KALibur and priate distance, with wide flange 3. Apply Kal-Mesh and Kal-Korner Plaster Systems. The Z Furring allow to set. pointing toward applicator, secure Bead according to procedures Channel is manufactured from Z Channel with appropriate fasten- described on pages 16 and 17. Exterior Corners galvanized steel (.0179” min. base ers, spaced 24" o.c. driven through 4. Mix and trowel on Kal-Kote steel) and is produced with web Install cornerbead with adhesive short flange. (Note: Power-driven Base and Finish Plaster or Uni-Kal depths of 1", 1-1/2" and 2". The at least 4 and preferably 16 hours fasteners are not recommended for Plaster as described on pages 18 furring channel which is applied to before plastering. Apply a continuous use with masonry block.) and 19. bead of adhesive approximately a masonry wall holds the insulation 1/4"x 1/4" along the inside of in place and the wide flange serves Install 24" wide floor-to-ceiling both cornerbead flanges. Press the as framing for the application of insulation panel, pressed snugly bead firmly over the corner so that the Kal-Kore plastering base. against web of first Z. Install next Z with the wide flange overlapping adhesive is in continuous contact Limitations with masonry surface. Align bead the edge of the first insulation 1. Since the interior wall surface and allow to stand undisturbed panel. Fasten Z to wall through will take the general configuration at least 4 hours. narrow flange. Continue in this of the masonry wall, it may be nec- manner with Z Furring member Kal-Kote Application essary when applying the system 24" o.c. to end of wall. Locate last Note: Application shall conform to to unit masonry to use portland Z so that web is located a distance ASTM C 843. cement plaster to bring the wall to equal to insulation thickness from a plane surface. adjoining wall. Cut last insulation Proceed with the full field of the wall panel to fit remaining space. by scratching-in tightly, then double 2. This system is mainly for new back immediately with material from masonry construction. On well-cured At exterior corner, attach the Z the same batch to a minimum thick- concrete or masonry, it may be through its wide flange with nar- ness of 1/16" over the block surface, difficult to properly drive fasteners. row flange extending beyond the or as required to level. 3. Power-driven fasteners shall corner. Begin with a narrow strip of floor-to-ceiling insulation, wider Kal-Kote Finishes should be kept be used only for attachment to than insulation thickness, but not as thin as possible and applied as monolithic concrete surfaces. exceeding 3". Continue application described on pages 18 and 19. 4. Kal-Kore should be applied within of furring and insulation progres- Uni-Kal or X-KALibur 24 hours of foam application. sively as described above. Application At windows, doors and trim areas, Caution: Since Uni-Kal or X-KALibur use wood nailers, nominal 2" wide is a one-coat material system, x insulation thickness plus 1/32". exercise care in leveling the wall to Use the nailers also at wall-floor compensate for the uneven suction. angles to support trim and provide Proceed with full field of the wall backing for base. by scratching-in tightly, then double back immediately with same batch of material to a minimum thickness of 3/32" over the block surface.

20 Veneer Plaster Problems and Solutions

Conditions/Causes/ The prime job conditions initiating m Improper or deficient substrate m Structural and framing Prevention/Correction problems are: for accepting plasters. irregularities and deficiencies. m m Veneer plaster problems are gener- Improper material storage and Some of the problems associated Fastening deficiencies. ally related to job conditions or handling. with veneer plaster construction m Structural movement. m have the same cause - prevention – abuses and marginal or improper Poor or improper plastering Attention to good plastering plastering techniques or practices practices and techniques. correction characteristics as drywall. These main common conditions are: practices and procedures will and infrequently to a product quality m Adverse or extreme environmental minimize or eliminate job site m deficiency. conditions. Gypsum base application problems and call-backs. deficiencies.

Condition Probable Cause Preventive Action Corrective Action IN-PLACE CONDITIONS Joint Cracking 1. Wrong type of reinforcing mesh 1–3. Use proper type of mesh and Large Cracks: Scrape crack or tape was used. recommended joint installation and apply drywall tape and setting 2. No reinforcing mesh was used, or procedures. – DO NOT USE SELF- type joint compound. improperly positioned over joint. STICK (PRESSURE SENSITIVE) MESH. Small Cracks: Fill and feather 3. Joint not pretreated prior to 4. Avoid hot, low humidity air, out area with ready mixed joint general plastering. high draft exposure. compound. 4. Rapid drying conditions. 5. Install control joints as required. 5. Expansion/contraction. 6. Avoid extreme and rapid tempera- 6. Thermal shock. ture differentials (thermal shock). 7. Structural movement. 7. Avoid jointing plaster base at corners of openings, stagger joints on opposite side of partition.

Random Or Map Cracking Concentrated stresses caused by Maintain minimum 55°F (18°C) Fill and feather area with ready differential shrinkage or expansion conditions prior to, during and after mixed joint compound. between plaster and substrate or plastering. between individual plaster coats – thermal shock.

Mud Cracking Rapid drying or too thin plaster Avoid rapid drying conditions, apply Apply ready mixed joint (Craze, Shrinkage, Alligator) application. plaster at recommended thickness. compound.

Dryout 1. Rapid drying conditions. 1. Avoid rapid drying conditions. General or large area “dry-outs” 2. Thin plaster application. 2. Apply plaster at recommended – remove plaster; vacuum or wipe 3. Excessive job addition or retarder. thickness. down surface, apply bonding agent 3. Avoid job additions of retarder. and replaster. Small areas – spray surface with water or alum solution to set plas- ter. Repair area with ready mixed joint compound for an acceptable surface.

Nail Pops 1. Nail or screw heads Follow recommended veneer plaster Remove plaster around fastener puncturing face paper. base application procedures. and seat it properly and drive an 2. Nails or screws not securely additional fastener about 1-1/2” driven, loose or improper type. away from the popped fastener. 3. Framing members out of align- Patch with plaster or ready mixed ment or lumber shrinkage. joint compound. 4. Plaster base not applied tight against framing members.

21 Condition Probable Cause Preventive Action Corrective Action IN-PLACE CONDITIONS (cont.) Joint Ridging Or Beading 1. Large gaps between adjacent 1–3. Apply undamaged plaster Sand the ridge or bead and apply Most commonly occurring plaster base boards. base board according to ready mixed compound and feather when steel studs (24" on center) 2. Improper/insufficient number/ recommended procedures using out areas. are used and rapid drying location of fasteners. proper fastening. conditions exist 3. Gypsum base board edges damaged. 4/5. Use recommended 4. Wrong type or no reinforcing reinforcing mesh or paper tape mesh used. and pretreat joints prior to gen- 5. Joints not pre-treated prior to eral plastering. general plastering. 6. Avoid rapid drying conditions. 6. Rapid drying conditions.

Rusting/Staining Of Finish Use of improper fasteners or metal Use only recommended fasteners Prime affected area with a primer/ trim. and trim. sealer and redecorate.

Photographing Or Ghosting 1. Differential in base plaster suction Apply basecoat plaster to full Prime affected area with a primer/ Of Joint Line between joint and field. thickness, following recommended sealer and redecorate. 2. Too thin a coat of base plaster procedures. overall, resulting in a very thin covering over mesh. 3. Partially dry base plaster, mois- ture content differential greater between joint and field.

Joint Shadowing Caused By Gypsum veneer base gapped Follow recommended veneer base Fill depression with joint compound or Depression Or Ridging causing a depression or ridge at and plaster application procedures. sand ridges flush with field, skim coat the joint line. with joint compound and redecorate.

Bond Failure Product Related Causes: The best advice for preventing Remove all loose or marginally Cause(s) of bond failure is 1. Use of pressure sensitive mesh – veneer plaster problems is to strictly bonded plaster, brush the surface perhaps the most difficult reduces plaster substrate contact. follow the manufacturer’s recom- thoroughly to remove dust (vacu- condition to diagnose because 2. “Setting” or “drying” type joint mendations and adhere to proper uming is recommended), apply a of the great number of factors compounds used to treat joints. plastering practices. quality bonding agent per manu- which can influence plaster Job Condition Causes: facturer’s recommendations and bonding 1. “Dry-out” or “partial dry-out” replaster. – plaster loses water prior to complete setting or hydration. 2. Using plaster which has been exposed to the atmosphere, open bags or improper storage. 3. Freezing of plaster before setting has occurred. 4. Application of plaster over frost on substrate. 5. Excessively rapid thermal changes. 6. Excessive thermal differences between the face and back of the plaster base. Application Practice Causes: 1. Application of lime containing plas- ter over light faded veneer base. 2. Use of retempered plaster, remixing with additional water plaster which has “bucked-up” (stiffened) or started to set to render it workable again. 3. Excessive delay in applying plaster after mixing – application near or into the initial setting action.

22 Condition Probable Cause Preventive Action Corrective Action IN-PLACE CONDITIONS (cont.) Bond Failure (cont.) 4. Excessive use of retarder to slow The best advice for preventing Remove all loose or marginally setting, so partial dry-out occurs. veneer plaster problems is to strictly bonded plaster, brush the surface 5. Adulteration of the plaster on the follow the manufacturer’s recom- thoroughly to remove dust job site by addition of substances mendations and adhere to (vacuuming is recommended), other than clean graded silica proper plastering practices. apply a quality bonding agent per sand or excessive use of sand. manufacturer’s recommendations 6. Application of plaster over and replaster. improper substrate. 7. Application of plaster over contaminated substrate, dust, dirt, oil, soot, etc. 8. Application of plaster over substrate with excessively high suction – too high absorptivity. 9. Application of plaster over sub- strate with inadequate absorp- tivity – too low suction. 10. “Laying-on” or “buttering-on” plaster without adequate trowel pressure to provide mechanical keying to the substrate. 11. Inadequate or insufficient fin- ish troweling. 12. Basecoat plaster troweled too smooth – reduces mechanical key- ing of finish to the base plaster. 13. Finish plaster applied over base- coat plaster too thick, and not tightly troweled into the base plaster. 14. One coat finish applied too thin. PALSTER APPLICATION CONDITIONS Hard (Set) Lumps In Package Plaster bags became wet Protect plaster from water 1. Screen out hard lumps before during transit or storage. during transit and storage. mixing. 2. Discard the plaster.

Set Time Variable Within 1. Improper mixing equipment. 1. Use recommended mixing See Prevention. The Same Job Mixed Batch 2. Insufficient water used at the equipment. start of mixing. 2. Add all but about 1 quart of the 3. Insufficient mixing time. recommended amount of water to the mixer at start. 3. Mix to a uniform fluidity; mixing time should not exceed 5 minutes.

Set Time Variable From 1. Dirty equipment 1. Use only clean equipment. See Prevention. Batch To Batch 2. No or improper equipment 2. Follow recommended equip- clean-out procedures. ment clean-out procedures. 3. Partial bag mixed. 3. Use only full bags.

Slow Set Plaster 1. Temperature below 40°F (4°C) 1. Avoid extremes of air, plaster 1/2. During cold weather maintain or in excess of 100°F (38°C). and mix water temperature. temperature between 55° and 2. Job addition of retarder. 2. Avoid job addition of retarder. 70°F before, during and after 3. Use of old, improperly stored 3. Use only properly stored plaster plastering. Avoid job additions of plaster or plaster from open bags from unopened bags, less than retarder. Cautiously use accelera- which have been exposed to air. a year old. tor to speed up setting action. 4. Partial bag mixed. 4. Use only full bags. 3. Replace material. 4. Use only full bags.

23 Condition Probable Cause Preventive Action Corrective Action PLASTER APPLICATION CONDITIONS (cont.) Quick Set 1. Dirty equipment. 1. Follow recommended clean-out 1–5. Follow good recommended 2. Excessive mixing. procedures. plastering practices. 3. Contaminated mixing water. 2. Do not exceed 5 minutes mixing 6. Cautiously use retarder to slow 4. Plaster has become wet or time. set time. contaminated prior to mixing. 3. Use only potable water. 7. Use only full bag. 5. Excessive use of accelerator. 4. Use only properly stored, uncon- 6. Excessively low air/plaster mix, taminated plaster. water temperatures below 40°F 5. Maintain construction areas and (4°C). materials above 55˚F prior to, 7. Partial bag mixed. during and after plastering. 6. Avoid job additions of accelerator. 7. Use only full bag.

Spreading Qualities 1. Improper mixing equipment/ Use recommended mixing equip- See Prevention. Vary Within Batch mixing action. ment, water ratio and procedure. 2. Insufficient water used at start of mixing. 3. Insufficient mixing time. 4. Aggregate separation.

Spreading Qualities Vary 1. Inconsistent mixing. 1. Follow recommended mixing See Prevention. From Batch To Batch 2. Using part or open bags exposed procedures. to air. 2/3. Use only full, unopened bags, 3. Old or improperly stored plaster. which have been properly stored. 4. Variable aggregate. 4. Replace aggregate and/or plaster.

Smooth Or Texture Finish 1. Surface of unset plaster being 1. Adjust finishing sequence to See Prevention. Desired, Not Obtained worked at wrong time, too stiff meet plaster condition. or too soft. 2. Gypsum Base: Adjust plaster 2. Suction of substrate too high or working time sequence to com- too low. pensate for high or low suction. 3. Surface of plaster being worked Basecoat Plaster: Apply finish after plaster has set. over “green” moderately dry 4. Intermixing material from different basecoat or dampen dry basecoat. manufacturers. 3. Follow recommended smooth or texturing procedures. 4. Use only materials from single producer to ensure compatibility.

Blistering Of Smooth Finish 1. Application of water onto the 1. Reduce trowel pressure during Eliminate blisters with strong A common condition, especially plaster surface with troweling “double-back” and “draw-up” trowel pressure during final water over “green” basecoat plaster, before sufficient stiffening operation. Use water sparingly troweling operation, when plaster less over gypsum veneer base (“take-up”) has occurred. and only after adequate plaster is firm and/or setting action in 2. Aggravated by cold plastering “take-up” has developed or ini- progress. surfaces. tial setting action has occurred. 2. Maintain recommended working area temperature.

Fuzzing Or Ragging Of 1. Finish plaster surface lacks 1. Wet trowel or sparingly apply See Prevention. Smooth Finish Surface sufficient water for adequate water on plaster surface during trowel lubrication or slip during “draw-up”. Avoid starting “draw- “draw-up” operation. up” too long after “take-up”. 2. Job-gauged finish components 2. Be sure job-gauged finish not uniformly blended, causing components are uniformly and localized dry spots due to thoroughly blended. uneven water retention. 3. Decrease trowel angle to surface, 3. Excessive trowel pressure, trowel ease up on trowel pressure or at wrong angle to the surface or start troweling sequence sooner. timing wrong for troweling. 24 Condition Probable Cause Preventive Action Corrective Action PLASTER APPLICATION CONDITIONS (cont.) Peeling And Tearing Of Smooth 1. “Double-back” coat of finish 1. “Scratch” and “double-back” See Prevention. Finish During Application troweled over “scratch” coat with finish from the same batch, which has stiffened excessively minimizing time between coats. or set. 2. Use only light, even trowel 2. Trowel pressure during “draw- pressure when “drawing-up”. up” too strong for stiffness and thickness of finish. DECORATING PROBLEMS Paint Peeling/Blisters 1. Plaster not completely dry. 1. Allow sufficient drying time 1/2. Remove all peeling/blistering Use only quality paints 2. Wrong type of paint used. before painting; consideration paint, allow sufficient drying specifically recommended by 3. Plaster surface chalky. to environmental conditions is time. Prime and redecorate. the paint manufacturer for 4. Plaster surface contaminated, imperative. 3. Remove all peeling paint, application over lime grease, soot. 2. Use only paint specifically rec- and brush surface to remove (alkaline) containing plasters 5. Plaster became wet after ommended by the paint manu- chalkiness. Apply primer recom- decoration was completed. facturer for use over new or mended by paint manufacturer freshly plastered surfaces. for chalky plaster surfaces. 3. Finish plaster per recommended practices, leave plaster surface under trowel, do not brush finish. 4. Examine plaster surface for signs of contamination prior to painting. 5. Make sure areas are weather tight before plastering and printing.

Joint Shadowing Depression or ridge at the joint See “Joint Shadowing Caused By See “Joint Shadowing Caused By line. Depression Or Ridging.” Depression Or Ridging.”

Paint “Stringing” or “Roping” 1. Wrong type of paint. 1. Use proper type of paint for 1. Stop painting. During Roll Application 2. Solids content of paint too high. plaster surfaces. 2. Check preventative measures 3. Fast drying conditions. 2. Dilute paint per manufacturer’s and make necessary corrections. 4. Plaster surface dusty. recommendations. 3. Allow painted area to dry and 3. Reduce drying conditions. repair by either sanding the 4. Make sure plaster is dust free. affected area or skimming with joint compound to a smooth surface and repaint. 4. Brush the surface thoroughly to remove dust (vacuuming is recommended).

Painting Plaster Various job conditions such as suction differences, wet or only partially dry walls, and reactions between paint and lime may cause unsatisfactory paint finishes particularly on new construction. Alkali-resistant primers specifically formulated for use over new plaster will permit decorating with oil or latex type paints. Quality paint products should be used and manufacturers’ recommendations followed. Finished plaster should be painted or covered to conceal possible discoloration. The paint system should be suitable for use over plaster surfaces that contain lime. It is essential that plaster be sound and completely dry before painting. Under good drying conditions, veneer plaster may be painted 48 hours after application.

25 Glossary of Terms

Accelerator ...... A substance used to shorten or speed up the setting action (time) of the plaster. Admixture ...... A substance other than water, or aggregate added to the plaster to alter its properties. Aggregate ...... An inert material used as a filler or texturing aid. Anhydrite...... An anhydrous form of gypsum. Basecoat...... A plaster coat applied over a substrate prior to application of the finish coat. Blistering ...... Bulging or separation of the wet finish plaster coat away from the base. Bond ...... Adhesion between plaster coats or between plaster and substrate produced by mechanical and chemical properties of the plaster, or intermediate bonding agents applied prior to plastering. Bonding Agent ...... An adhesive substance applied to a substrate to provide a medium for plaster bond. Brown Out ...... A darkening of the exposed plaster surface indicating setting action is complete. Buck-Up ...... A premature stiffening of plaster mortar shortly after mixing. Usually indicates a plaster deficiency or an adverse reaction to a job addition of aggregate. Calcine ...... To drive off water of crystallization by heating. Calcined Gypsum ...... Gypsum with 1-1/2 molecules of combined water removed – also called plaster, stucco, hemihydrate, semihydrate. Cat Face ...... A blemish or rough depression in the finish coat plaster. Chemical Bond ...... Bond produced by the formation and subsequent interlocking of gypsum crystals during the setting process. Coat...... A thickness, covering, or layer of plaster applied in a single operation. Consistency ...... An amount of water required to bring a unit weight of dry plaster to a workable fluidity. Craze Cracks ...... Fine random fissures or cracks in the plaster surface caused by plaster shrinkage due to loss of water before setting. Cure...... The state of or conditions conducive to complete hydration of the plaster. Dolomite ...... A type of lime or limestone containing calcium with up to 50% magnesium as the hydroxide or carbonate. Double-Up ...... Plaster placement characterized by application of material from the same mixed batch in successive operations without setting or drying allowed between coats – double-back, laid-off, or two-coat work. Draw-Up...... The troweling process after the applied finish plaster has “taken up”, whereby surface irregularities are filled and leveled with or without the use of fresh plaster on the tools. Dry-Out...... A condition where some or all of the water necessary for plaster hydration is lost by evaporation or excessive suction. Efflorescence...... A white, fleecy surface deposit of salts. Fat ...... Soft usable plaster accumulated on trowel during finishing operation, often used to fill in small imperfections. Finish Coat...... The last layer of plaster applied – smooth or texture. Finishing Brushes ...... Brushes used to dash water onto the surface of finish plaster during smooth troweling. Float ...... Tool or procedure used to straighten and level the finish coat surface to correct surface irregularities produced by other tools and to impart a distinctive surface texture. Float Finish ...... A finish coat texture derived primarily from aggregate particles in the plaster. Gauging ...... Gypsum plaster added to lime putty to provide and control set. Green ...... Newly applied plaster that has set but not completely dried out. Hawk...... Tool used by plasterers to hold and carry plaster mortar, in conjunction with troweling. Hemihydrate ...... Calcined gypsum. High Calcium Lime...... The oxide or hydroxide derived from limestone, which is principally calcium carbonate. The product contains less than 5% magnesium oxide or hydroxide. Hydrate...... Term used to denote hydrated lime. Hydrated Lime ...... Quicklime (oxide) which has been hydrated to yield the hydroxide, a dry powder. Joining ...... The juncture of two separate plaster applications on a common surface. Landplaster ...... Ground natural gypsum. Lay Down...... The troweling process after the applied finish plaster has “taken up”, whereby surface irregularities are filled and leveled with or without the use of fresh plaster on the tools.

26 Lean Mixture...... High aggregate to plaster ratio; often exhibits poor working qualities. Light Weight Aggregate ...... Expanded perlite or vermiculite. Lime...... Oxides or hydroxides of calcium or calcium and magnesium. Lime Putty ...... A thick paste obtained by “slaking” quicklime or soaking and mixing hydrated lime with a minimum of water. Mechanical Bond ...... Physical keying of plaster to substrate. Mill Mixed ...... Plasters requiring only water addition on the job site. Mortar ...... A material used in plastic state which can be troweled and hardens after placement. Mud Cracks ...... Fine random cracks in the plaster surface caused by plaster shrinkage due to loss of water (dry-out) before setting. Perlite ...... A siliceous volcanic glass – expanded by heating into a lightweight plaster aggregate. Plaster Bond ...... Adhesion between plaster coats or between plaster and a plaster substrate produced by a mechanical and chemical interlocking of plaster with the substrate. Purity ...... The percentage of calcium sulfate dihydrate contained in a fully hydrated gypsum plaster. Relative Humidity ...... The ratio of the amount of water vapor actually present in the air to the greatest amount possible at the same temperature, expressed as a percentage. Retarder...... A material added to plaster which will lengthen the setting time. Retemper...... To mix additional water with plaster which has begun to stiffen or set so as to render it workable again. Sand ...... A washed and size-graded, granular natural material (aggregate) added to veneer plasters to aid float texturing of the plaster. Scratch And Double...... Plaster application characterized by a tight application of plaster against the substrate and immediately followed by a second application of plaster from the same batch of mixed plaster. Setting Time ...... The elapsed time after mixing with water for the plaster to harden or hydrate. Sweeten ...... The troweling process after the applied finish plaster has “taken up”, whereby surface irregularities are filled and leveled with or without the use of fresh plaster on the tools. Take-Up ...... A normal stiffening of the applied plaster resulting from the removal of water from the plaster by absorption (suction) into the substrate. Trowel Finish...... Denotes a smooth finish surface produced by troweling. Veneer Plaster ...... A specially manufactured gypsum plaster which provides strength, hardness and abrasion resistance and is capable of thin application over designated substances. Veneer Plaster Base ...... A gypsum board with special paper facing designed to provide water absorption for rapid veneer plaster application and finishing. Workability ...... The ease and speed with which plaster mortar can be applied and finished.

27 Technical Data LIMITED WARRANTY CUSTOMER SERVICE SALES AREAS AND REMEDIES Products manufactured and sold by National Gypsum are warranted by National Gypsum to its customers to be free from defects in materials and workmanship at the time of shipment. THIS EXPRESS WARRANTY IS THE ONLY WARRANTY APPLICABLE TO SUCH PRODUCTS, AND IS IN LIEU OF AND EXCLUDES ALL OTHER EXPRESS ORAL OR WRITTEN WARRANTIES AND ALL IMPLIED WARRANTIES, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. National Gypsum will not be liable for any incidental, indirect or consequential losses, damages or expenses. The customer’s exclusive remedy for any type of claim or action for defective products will be limited to the replacement of the products (in the form originally shipped) or, at National Gypsum’s option, to a payment or credit not greater than the original purchase price of the products. National Gypsum will not be liable for products claimed to be defective where the defect resulted from causes not within National Gypsum’s control, or which arose m Atlantic Area m Northeast Area National Accounts or occurred after shipment, including but Phone: (800) 237-9167 Phone: (800) 253-3161 Phone: (800) 440-1230 not limited to accidents, misuse, mishandling, improper installation, contamination or Fax: (877) 252-0430 Fax: (866) 632-1480 Fax: (866) 622-3590 adulteration by other materials or goods, m Central Area m Southeast Area Manufactured Housing or abnormal conditions of temperature, moisture, dirt or corrosive matter. Phone: (800) 252-1065 Phone: (800) 548-9394 Phone: (800) 455-3185 Any claim that products sold by National Fax: (866) 232-0440 Fax: (866) 732-1990 Fax: (800) 639-1714 Gypsum were defective or otherwise did m Gulf Area m Southwest Area not conform to the contract of sale is Phone: (800) 343-4893 Phone: (800) 548-9396 waived unless the customer submits it in writing to National Gypsum within thirty Fax: (866) 482-8940 Fax: (866) 792-7520 (30) days from the date the customer m Midwest Area m Western Area discovered or should have discovered the defect or nonconformance. No legal action Phone: (800) 323-1447 Phone: (800) 824-4227 or proceeding complaining of goods sold Fax: (866) 692-8590 Fax: (800) 438-6266 by National Gypsum may be brought by the customer more than one year after the date the customer discovered or should have discovered the defect or problem of which it complains.

Corporate Headquarters Technical Information National Gypsum Company Phone: (800) NATIONAL 2001 Rexford Road (800) 628-4662 Charlotte, NC 28211 Fax: (800) FAX-NGC1 Phone: (704) 365-7300 (800) 329-6421 Web: nationalgypsum.com nationalgypsum.com/espanol 110753 Rev. 7/14