1、Designation: C 844 04Standard Specification forApplication of Gypsum Base to ReceiveGypsum Veneer Plaster1This standard is issued under the fixed designation C 844; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last r
2、evision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defense.1. Scope*1.1 This specification covers the minimum req
3、uirements for,and methods of, application of gypsum veneer base for gypsumveneer plasters.1.2 Gypsum veneer base shall not be used as a base fordirect adhesive application of ceramic, metal, or plastic tile inareas exposed to abnormal moisture or humidity or tempera-ture.1.3 Details of construction
4、for a specific assembly toachieve the required fire resistance shall be obtained fromreports of fire-resistance tests, engineering evaluations, orlistings from recognized fire testing laboratories.1.4 Where a specific degree of sound control is required forveneer plaster assemblies and constructions
5、, details of con-struction shall be in accordance with official reports of testsconducted in recognized sound testing laboratories in accor-dance with the applicable sound tests, Test Method C 423, TestMethod E 90, or Test Method E 492.1.5 Where this specification is more stringent (size orthickness
6、 of framing; spacing of fasteners) than the fire-ratedconstruction, this specification shall govern; otherwise, theconstruction described in the fire test report shall govern.1.6 Unheated spaces above gypsum veneer base ceilingsshall be properly ventilated (see Appendix X3).1.7 The values stated in
7、inch-pound units are to be regardedas the standard. The SI (metric) values given in parentheses areapproximate and are provided for information purposes only.1.8 The text of this standard references notes and footnoteswhich provide explanatory material. These notes and footnotes(excluding those in t
8、ables and figures) shall not be consideredas requirements of the standard.2. Referenced Documents2.1 ASTM Standards:2C 11 Terminology Relating to Gypsum and Related Build-ing Materials and SystemsC 423 Test Method for Sound Absorption and Sound Ab-sorption Coefficients by the Reverberation Room Meth
9、odC 514 Specification for Nails for the Application of Gyp-sum BoardC 587 Specification for Gypsum Veneer PlasterC 588 Specification for Gypsum Base for Veneer PlastersC 754 Specification for Installation of Steel Framing Mem-bers to Receive Screw-Attached Gypsum Panel ProductsC 954 Specification fo
10、r Steel Drill Screws for the Applica-tion of Gypsum Panel Products or Metal Plaster Bases toSteel Studs from 0.033 in. (0.84 mm) to 0.012 in. (2.84mm) in ThicknessC 955 Specification for Load-Bearing (Transverse andAxial) Steel Studs, Runners (Tracks), and Bracing orBridging for Screw Application of
11、 Gypsum Panel Productsand Metal Plaster BasesC 1002 Specification for Steel Self-Piercing TappingScrews for the Application of Gypsum Panel Products orMetal Plaster Bases to Wood Studs or Steel StudsC 1007 Specification for Installation of Load BearingTransverse and AxialC 1047 Specification for Ins
12、tallation of Load Bearing(Transverse and Axial) Steel Studs and Related Accesso-riesC 1546 Guide for Installation of Gypsum Products in Con-cealed Radiant Ceiling Heating SystemsE 90 Test Method for Laboratory Measurement of AirborneSound Transmission Loss of Building Partitions and Ele-ments1This s
13、pecification is under the jurisdiction of ASTM Committee C11 onGypsum and Related Building Material and Systems, and is the direct responsibilityof Subcommittee C11.03 on Specifications for Application of Gypsum and OtherProducts in Assemblies.Current edition approved Oct. 1, 2004. Published October
14、 2004. Originallyapproved in 1978. Last previous edition approved in 1999 as C 844 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary
15、 page onthe ASTM website.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.E 492 Test Method for Laboratory Measurement of ImpactSound Transmission Through Floor-Ceiling
16、 AssembliesUsing the Tapping Machine2.2 American Softwood Lumber Standard:PS20 American Softwood Lumber Standard33. Terminology3.1 DefinitionsDefinitions shall be in accordance withTerminology C 11.3.2 Definitions of Terms Specific to this Standard:3.2.1 base plyfirst ply of gypsum base in multiple
17、plyapplication.3.2.2 face plyouter or visible layer of gypsum base inmultiple ply application.3.2.3 fastener, nnails, screws, or staples used for theapplication of the gypsum base or backing board.3.2.4 framing member, nthat portion of the framing,furring, blocking, etc., to which the gypsum base is
18、 attached.Unless otherwise specified, the surface to which abutting edgesor ends are attached shall be not less than 112 in. (38 mm)wide for wood members, not less than 114 in. (32 mm) widefor steel members, and not less than 6 in. (152 mm) wide forgypsum studs. For internal corners or angles, the b
19、earingsurface shall be not less than34 in. (19 mm).3.2.5 parallel application, ngypsum base applicationwhere the gypsum base edge is applied parallel to the framingmembers.3.2.6 perpendicular application, ngypsum base applica-tion where the gypsum base edge is applied at right angles tothe framing m
20、embers.4. Materials4.1 Materials shall conform to the respective specificationsand standards and to the requirements specified herein.4.2 Gypsum Base for Veneer Plasters (hereinafter referredto as “gypsum base”)Specification C 588.4.3 Gypsum Backing Board or CoreboardSpecificationC 442.4.4 Special F
21、ire-Retardant Gypsum BaseSpecificationC 588, Type X.4.5 Foil-Backed Gypsum BaseSpecification C 588.4.6 Gypsum Veneer PlasterSpecification C 587.4.7 NailsSpecification C 514.4.8 Screws:4.8.1 Non-load bearing steelSpecification C 1002.4.8.2 Load bearing steelSpecification C 954.4.9 StaplesNo. 16 USS g
22、age 0.063 in. (1.6-mm) flattenedgalvanized wire with716-in. (11.1-mm) wide-crown minimumoutside measure and divergent points. Staples shall be usedonly for the base ply of two-ply application over woodframing.4.10 Steel Framing, Non-load bearingSpecificationC 645 for the specified design criteria.4.
23、11 AccessoriesSpecification C 1047.4.12 Adhesive:4.12.1 For application of gypsum base to steel framing, theadhesive shall be as recommended by the manufacturer of thegypsum base.4.13 Steel Framing Load BearingSpecification C 955.4.14 Wood FramingAmerican Lumber Softwood Stan-dard PS20.5. Delivery o
24、f Materials5.1 All materials shall be delivered in the original packages,containers, or bundles bearing the brand name and manufac-turer (or supplier) identification.6. Shipping, Handling and Storage6.1 Gypsum board shall be shipped so as to be kept dry.6.2 Gypsum board shall be stored so as to be k
25、ept dry,preferably inside a building, under a roof. Gypsum board shallbe neatly stacked flat with care taken to prevent sagging ordamage to edges, ends, and surfaces.6.3 Where necessary to store gypsum board outside, it shallbe stacked flat, off the ground, supported on a level platformand fully pro
26、tected from weather and direct sunlight exposure.6.4 Prior to application, the building exterior shall be soenclosed to protect the gypsum base from exposure to weatherand direct sunlight.NOTE 1The bond of alkaline veneer plaster to gypsum base will beimpaired if the base is exposed to direct light
27、or sunlight for extendedperiods.7. Environmental Conditions7.1 Application of Gypsum Base and AdhesivesA roomtemperature of not less than 40 F (4 C) shall be maintainedduring application of gypsum base except when adhesive isused for the attachment of gypsum base. For the bonding ofadhesive, a room
28、temperature of not less than 50 F (10 C)shall be maintained for 48 h prior to application and continu-ously thereafter until adhesive is completely dry. When atemporary heat source is used, the temperature shall not exceed95 F (35 C) in any room or area. Adequate ventilation shallbe maintained in th
29、e working area during the application andadhesive curing process.8. Application of Gypsum Base8.1 General Requirements:8.1.1 Installation of steel framing shall be in accordancewith applicable Specifications C 754 or C 1007 except wheresuperseded by requirements of Table 1.NOTE 2For general wood fra
30、ming requirements, see Appendix X2.8.1.2 Method of CuttingThe gypsum base shall be cut byscoring and breaking or by sawing, working from the face side.When cutting by scoring, the face shall be cut with a knife orother suitable tool and the gypsum base snapped back awayfrom the cut face. The back sh
31、all be broken by snapping thegypsum base in the reverse direction, or by cutting with a knifeor other suitable tool.8.1.3 All cut edges and ends of the gypsum base shall besmoothed to obtain neat jointing. Cut-outs for pipes, fixtures,or other small openings on the face and back of the base shallbe
32、scribed in outline before removing or cut out with a saw or3Available from National Institute of Standards and Technology, Gaithersburg,MD 20899.C844042other suitable tool. The gypsum base shall be scribed where itmeets projecting surfaces. Base shall be brought lightly intocontact with adjacent pan
33、els but not forced into place. Abuttingends and edges shall fit neatly.8.1.4 When gypsum base is to be applied to both ceiling andwalls, the base shall be applied to the ceiling and then to thewalls.8.2 Fastening, Mechanical:8.2.1 The gypsum base shall be held in firm contact with theunderlying supp
34、ort while driving any fastener.8.2.2 Fastener application shall proceed from the center ofthe field of the gypsum base to the ends and edges or shallbegin along one edge and proceed toward the other edge.8.2.3 Except where required for fire rating, structural per-formance, or other special considera
35、tions, fastening to top orbottom plates shall not be required.8.2.4 Fasteners shall be spaced not less than38 in. (9.5 mm)from the edges and ends of the gypsum base. Fasteners used atedges or at base ends in horizontal application shall not bemore than 1 in. from edges or ends.8.2.5 Nails and screws
36、 shall be driven to a point flush withthe gypsum base surface without breaking the surface paper ordamaging the surrounding gypsum core and without strippingthe framing member around the screws.8.2.6 Staples shall be driven so that both legs penetrate thesupport member and the crown bears tightly ag
37、ainst thebacking board, but does not cut into the face paper. The stapleshall be driven with the crown parallel to framing members.Staples shall be used only for the first ply in two-ply gypsumbase systems.8.2.7 Penetration of mechanical fasteners into supportingframing members shall be not less tha
38、n:Nails Screws StaplesWood:78 in. (22 mm)58 in. (15 mm)58 in. (15 mm), each legSteel: .38 in. (9 mm) .8.3 Control Joints8.3.1 Control joints shall be installed in ceilings more than2500 ft2(232 m2) in area that are constructed with perimeterrelief. The distance between control joints shall be not mo
39、rethan 50 ft (15 m) in either direction.8.3.2 Ceilings of more than 900 ft2(85 m2) in area con-structed without perimeter relief shall have control jointsinstalled with spacing not to exceed 30 ft (9 m) in eitherdirection.8.3.3 Control joints shall be installed where ceiling framingor furring change
40、s direction or where construction joints occurin the base building construction. In partitions, walls, or wallfurring, the distance between control joints shall be not morethan 30 ft (9 m).8.3.4 A ceiling height door frame, installed in accordancewith the spacing requirements set forth in 8.3, funct
41、ions as acontrol joint.9. Application of Single-Ply Gypsum Base9.1 The maximum spacing of framing members for single-ply gypsum base construction shall be not more than thoseshown in Table 1.9.2 In single-ply installation, all ends and edges of gypsumbase shall occur over framing members or other so
42、lid backingexcept where treated joints occur at right angles to framing orfurring members.9.3 Joints on opposite sides of a partition shall be arrangedto occur on different framing members.9.4 Fasteners (Single Ply Application):9.4.1 Nail SpacingSpace nails a maximum of 7 in. (178mm) on centers on t
43、he ceiling and a maximum of 8 in. (203mm) on centers on the walls.9.4.2 Double NailingNails shall be spaced as shown inFig. 1 and applied as follows:9.4.2.1 Starting at the center of the base, nails shown assolid dots shall be applied by row starting with row 1, thenrows 2 and 2A, 3 and 3A, 4 and 4A
44、. Base shall be kept tightagainst the framing throughout the procedure.9.4.2.2 Using the procedure in 9.4.2.1, second nails shownby circles shall be applied.9.4.2.3 As an alternative procedure, second nails shall bepermitted to be applied immediately after all first nails in eachindividual row have
45、been driven in accordance with 9.4.2.1.9.4.2.4 Single nails shall be used on the perimeter of thebase.NOTE 3It may be necessary to reset the first nails in each row after thesecond nails have been set.9.4.3 Nails for single-ply application over wood membersshall be as follows:TABLE 1 Maximum Framing
46、 SpacingSingle-ply Base (Thickness), in. (mm) Application to FramingMaximum On Center Spacing ofFraming, in. (mm)Ceilings:12 (12.7)12 (12.7)A58 (15.9)Bparallelperpendicularperpendicular16 (406)24 (610)24 (610)Sidewalls:38 (9.5)Cperpendicular 16 (406)12 (12.7) parallel 16 (406)12 (12.7)Aperpendicular
47、 24 (610)58 (15.9)Bparallel or perpendicular 24 (610)A 12-in. (12.7-mm) gypsum base applied perpendicular on 24-in. (610-mm) on centers framing shall be considered to be minimum construction.BFor58-in. (15.9-mm) base, perpendicular on ceilings and either perpendicular or parallel on sidewalls at 24-
48、in. (610-mm) on centers spacing, only two-componentveneer plaster or special joint reinforcement, as recommended by the gypsum veneer plaster manufacturer, shall be used.C 38-in. (9.5-mm) gypsum base shall be used over wood framing with two-component veneer plaster systems only.C844043Gypsum Base Th
49、ickness, in. (mm) Nails, in. (mm)38 (9.5) 114 (32)12 (12.7) 138 (35)58 (15.9) 112 (38)9.4.4 Where a specific degree of fire resistance is requiredfor gypsum board assemblies and constructions, nails of sameor larger length, shank diameter, and head bearing area, asthose described in the applicable fire test report shall be used.9.4.5 Screw SpacingScrews shall be spaced not more than12 in. (305 mm) on center along framing members for wall orceiling application.9.5 Floating Interior AnglesThe floating angle method ofapplicat
