1、Designation: C843 99 (Reapproved 2012)C843 17Standard Specification forApplication of Gypsum Veneer Plaster1This standard is issued under the fixed designation C843; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last
2、revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope Scope*1.1 This specification covers the
3、minimum requirements for and methods of applying gypsum veneer plaster.1.2 Where a specific degree of fire resistance is required for veneer plaster systems, applicable building code regulations shallbe followed.1.2.1 Details of construction for a specific assembly to achieve the required fire resis
4、tance shall be obtained from reports offire-resistance tests, engineering evaluations, or listings from recognized fire testing laboratories.1.3 Where a specific degree of sound control is required for veneer plaster assemblies and constructions, details of constructionshall be in compliance with of
5、ficial reports of tests conducted in recognized sound testing laboratories in accordance with theapplicable sound tests of Test Methods E90, C423, or E492.NOTE 1To ensure desirable results, coordinate this specification with Specification C844.NOTE 2General information regarding matters of a contrac
6、tual nature concerning veneer plaster work is found in Appendix X1. Additional technicalinformation related to veneer plastering is provided in Appendix X2.1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for informationonly.1.5 The te
7、xt of this specification references notes and footnotes which provide explanatory material. These notes and footnotes(excluding those in tables and figures) shall not be considered as requirements of the specification.1.6 This international standard was developed in accordance with internationally r
8、ecognized principles on standardizationestablished in the Decision on Principles for the Development of International Standards, Guides and Recommendations issuedby the World Trade Organization Technical Barriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2C11 Terminology Rel
9、ating to Gypsum and Related Building Materials and SystemsC423 Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room MethodC587 Specification for Gypsum Veneer PlasterC588/C588M Specification for Gypsum Base for Veneer Plasters (Withdrawn 2005)3C631 Specificati
10、on for Bonding Compounds for Interior Gypsum PlasteringC844 Specification for Application of Gypsum Base to Receive Gypsum Veneer PlasterC1047 Specification for Accessories for Gypsum Wallboard and Gypsum Veneer BaseE90 Test Method for Laboratory Measurement of Airborne Sound Transmission Loss of Bu
11、ilding Partitions and ElementsE492 Test Method for Laboratory Measurement of Impact Sound Transmission Through Floor-Ceiling Assemblies Using theTapping Machine3. Terminology3.1 Definitions:3.1.1 See Terminology C11.1 This specification is under the jurisdiction of ASTM Committee C11 on Gypsum and R
12、elated Building Materials and Systems and is the direct responsibility ofSubcommittee C11.03 on Specifications for the Application of Gypsum and Other Products in Assemblies.Current edition approved March 1, 2012May 1, 2017. Published June 2012May 2017. Originally approved in 1976. Last previous edi
13、tion approved in 20062012 asC843C843 99 (2012).99 (2006). DOI: 10.1520/C0843-99R12. 10.1520/C0843-17.2 For referencedASTM standards, visit theASTM website, www.astm.org, or contactASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to the standards Do
14、cument Summary page on the ASTM website.3 The last approved version of this historical standard is referenced on www.astm.org.This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becau
15、seit may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.*A Summary of Changes section appear
16、s at the end of this standardCopyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States13.2 Definitions of Terms Specific to This Standard:3.2.1 base coat, nveneer plaster trowel or machine applied as the first coat of a two-component system.3.2
17、.2 finish coat, nveneer finish plaster trowel or machine applied as the second coat over the base coat plaster in atwo-component system.3.2.2.1 smooth-trowel finish, na finish resulting from steel troweling with a minimum of water after the plaster has becomefirm. A smooth finish free of trowel mark
18、s, blemishes, or other imperfections.3.2.2.2 texture finish, na finish resulting from (1) trowel application followed by floating or texturing of the surface with anyof a variety of tools using a minimum of water or (2) machine application, left as applied or followed by hand texturing.3.2.3 joint-r
19、einforcing embedment, nthe cementitious material used to embed the strip material that is compatible with theveneer plaster used.3.2.4 one-component system, na veneer plaster system designed for application directly over approved bases in a single plastermix applied in a single coat or double-back o
20、peration with the same material.3.2.5 reinforced joint, na joint between gypsum base that is reinforced with strip material embedded in a cementitiousmaterial.3.2.6 reinforcing, njoint reinforcing tape or mesh (strip material) that is applied over flat joints and interior angles.3.2.7 two-component
21、system, na veneer plaster system involving two separate materials mixed and applied separately for basecoat and finish coat.3.2.8 veneer plaster system, ngypsum veneer plaster applied to (1) a gypsum base in accordance with 10.1 or (2) properlyprepared masonry or monolithic concrete surfaces, neithe
22、r side of which is exposed to moisture. The plaster shall be applied withone or more components not exceeding 14 in. (6.4 mm) in total thickness.4. Delivery of Materials4.1 All manufactured materials shall be delivered in the original packages, containers, or cartons bearing the brand name andmanufa
23、cturer identification.5. Protection of Materials5.1 Plasters and other cementitious materials shall be kept dry until ready to be used; they shall be kept off the ground, undercover, and away from damp walls and surfaces.6. Environmental Conditions6.1 TemperatureWhen the ambient outside temperature
24、at the building site is less than 55 F (13 C), 55F (13C), maintaina temperature in the building of not less than 55 F (13 C) 55F (13C) or not more than 80 F (27 C) 80F (27C) for not lessthan 24 h prior to the application of veneer plaster and for one week after the veneer plaster has set or until th
25、e veneer plaster hasdried. Distribute heat evenly in all work areas, and use deflection or protective screens to prevent concentrated or uneven heat orcold on the veneer plaster.NOTE 3The requirements in 6.1 will minimize the cracking of veneer plaster due to structural movements caused by thermal c
26、hanges fromtemperature extremes; and dry-outs due to hot spots caused by concentrated heat.6.2 VentilationVentilation shall be provided to remove excess water given off through the drying process.7. Materials7.1 Gypsum Base for Veneer Plasters (hereinafter referred to as “gypsum base”) Specification
27、 C588/C588M.7.2 Veneer PlastersSpecification C587.7.3 ReinforcingNoncorrosive strip providing the joint strength requirements of Specification C587.7.4 Liquid Bonding CompoundsSpecification C631 (see X2.3).7.5 WaterWater shall be clean, fresh, and of potable water quality.7.6 AccessoriesSpecificatio
28、n C1047.8. Surface Preparation8.1 ExaminationCarefully examine all surfaces, including but not limited to, unit masonry, monolithic concrete, gypsum basesof all types, and accessories to receive veneer plaster, before the veneer plaster is applied. Notify the proper authorities promptlyof all unsati
29、sfactory conditions. The examination shall determine whether the gypsum base has been exposed to excessive sunlight.Do not apply veneer plaster until after such unsatisfactory conditions are rectified to the satisfaction of the plastering contractor.NOTE 4The bond of alkaline veneer plaster to gypsu
30、m base may be impaired if the base is exposed to direct light or sunlight for extended periods.C843 1728.1.1 Do not apply veneer plaster over any surfaces of unit masonry or concrete that have been coated with any bituminouscompound or other waterproofing or damproofing or form release agent.8.2 Con
31、ditioning of Surfaces:8.2.1 Immediately before the plaster is applied, wet down the masonry surfaces on which suction shall be reduced. Visible watershall not remain on the surface.8.2.2 Carefully examine accessories, such as corner beads, control joints, casing beads, etc., and so forth, to ensure
32、that theyare straight, curved, plumb, level, square, or true to the required angles and have been applied in a manner to ensure full coverageof flanges before the plaster is applied.8.3 Monolithic Concrete SurfacesClean monolithic concrete surfaces of all dust, loose particles, and other foreign mat
33、ter.Completely remove all grease, oil, noncompatible curing compounds, and form releasing agents. Remove all ridges and protrusionsgreater that 18 in. (3.2 mm) and fill all depressions greater than 14 in. (6.4 mm) level with portland cement mortar and allow to setand dry. Any further preparation sha
34、ll be as recommended by the veneer plaster manufacturer.8.4 Gypsum Base Joint ReinforcementReinforce all interior angles and flat joints prior to application of the veneer plaster overthe base.8.4.1 Interior AnglesPosition and secure reinforcement with staples (on 12-in. (305-mm) centers, one side o
35、nly), veneerplaster, or other cementitious material compatible with the veneer plaster or by using self-adhering strip reinforcement. Whenstapling, staple along the ceiling edge only for wall-to-ceiling angles and along one edge for wall-to-wall angles. When securingreinforcement with veneer plaster
36、, reinforcement shall be thoroughly embedded so that embedment material is both under andcovering reinforcement.8.4.2 Flat JointsCenter reinforcement over the joint line of the gypsum base and secure with staples or veneer plaster if notusing self-adhering reinforcement. Keep reinforcement tight and
37、 flat against the gypsum base, and when stapling, position thestaples no farther than 24 in. (610 mm) apart, staggered along each edge. Embed reinforcement and continue application of theveneer plaster over the field of the base. (WarningThis method provides minimum reinforcement of the joints. To m
38、inimizeincidence and severity of joint ridging and cracking, use one of the following methods (8.4.2.1, 8.4.2.2, or 8.4.2.3) in the absenceof any specific method recommended by the veneer plaster manufacturer. Where paper tape and setting-type joint compounds areused, use 8.4.2.3.)8.4.2.1 Reinforcem
39、ent over Set Veneer PlasterTightly trowel veneer plaster over the joint line leaving the plaster feathered outto a width of about 6 in. (152 mm) flush with the face of the gypsum base.Allow the plaster to set; then secure reinforcement overthe joint line as described in 8.4.2.8.4.2.2 Reinforcement S
40、ecured and Embedded with Veneer PlasterApply reinforcement over the joint line as described in8.4.2. Tightly trowel the plaster over the reinforcement along the joint line to provide thorough embedment of the reinforcement.Allow the joint embedment to set before proceeding with general plastering.8.
41、4.2.3 Reinforcement Embedded (no staples)Tightly trowel the embedment material to a depth of about 132 in. (0.8 mm),(0.8 mm), working the trowel in both directions along the joint line. Center the reinforcement over the joint line. Firmly and evenlypress the reinforcement into the soft embedment mat
42、erial using a little soft material on the trowel to bury it completely, and leavethe embedment material feathered out to a width of about 6 in. (152 mm) flush with the face of the gypsum base. Allow theembedment material to set before proceeding with general plastering.9. Mixing9.1 Do not use frozen
43、, caked, or lumpy material. Do not retemper or use material that has partially set. Mix each batchseparately. Clean mixers thoroughly after each batch so as not to accelerate the following batches.This can be done by spray hosingthe mixer paddle and containers immediately after each batch. Water rat
44、ios and other techniques used for mixing shall conformto the manufacturers recommendation for specific veneer plaster products. In the absence of explicit directions, follow therecommendations in X2.1.9.2 Setting TimeSetting times are carefully controlled by the manufacturer. Do not make adjustments
45、 to the setting time onthe job. If problems with setting develop under unusual job conditions, consult the manufacturer of the veneer plaster forrecommendations.9.2.1 Do not use gauging, molding, or casting plasters, lime, gypsum, Keenes cement, portland cement, etc. and so forth toadjust the veneer
46、 plaster setting time.9.3 Occasionally, special textures are desired that require additional sand. Approval of the veneer plaster manufacturer shall beobtained prior to any such additions.10. Application10.1 GeneralVeneer plasters have widely differing working properties, physical characteristics, a
47、nd limitations regarding theircompatibility with one another and with various bases. Follow the particular methods, techniques, limitations, and procedures setforth by individual manufacturers for their product. In the absence of manufacturers directions, follow the recommendations inX2.2.C843 17310
48、.2 Plaster ThicknessMeasure the plaster thickness from the face of the base to which it is applied, exclusive of jointtreatment. The minimum thickness shall be as recommended by the manufacturer of the plaster used but in no case less than shownas follows:Base coats (trowel applied) 116 in. (1.6 mm)
49、 minBase coats (spray applied) 116 in. (1.6 mm) minFinishes (two-component systems) 132 in. (0.8 mm) to 116 in. (1.6 mm) minOne-component systems 116 in. (1.6 mm) minBase coats (trowel applied) 116 in. (1.6 mm) minBase coats (spray applied) 116 in. (1.6 mm) minFinishes (two-componentsystems)132 in. (0.8 mm) to 116 in. (1.6mm) minOne-component systems 116 in. (1.6 mm) min10.3 Barriers shall be provided to prevent the free circulation of hot, dry winds over the face of freshly applied plaster.11. Electric Radiant Heat
