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ASTM C842-05(2015) Standard Specification for Application of Interior Gypsum Plaster

ASTM C842-05(2015) Standard Specification for Application of Interior Gypsum Plaster


1.1 This specification covers the minimum requirements for full-thickness (in accordance with Table 1) interior gypsum plastering on gypsum, metal, masonry, or monolithic concrete bases designed or prepared to receive gypsum plaster.

(A) Base coat plastering of the same proportions as specified for unit masonry is not prohibited from being used over plain or reinforced monolithic concrete, provided the surface is first covered with a metal plaster base or first coated with a bonding compound.
(B) Finish coat plaster applied direct to a bonding compound over vertical monolithic concrete shall be not more than ³/16 in. (4.8 mm) in thickness. Where more than ³/16 in. of finish coat is required to bring such vertical surface to a true plane, a base coat of plaster shall first be applied to the bonding compound.
(C) Where horizontal or vertical monolithic concrete surfaces require more than ³/8 in. (9.5 mm) or 5/8 in. (15.9 mm) of plaster, respectively, to produce required lines or surfaces, metal plaster base shall be attached to the concrete before application of plaster. Where concrete surface requires the application of more than 1 in. (25.4 mm) of plaster to produce required lines or surfaces, lath shall be applied over furring secured to the concrete.

Typo corrected editorially October 2010.

1.1.1 Gypsum plaster applied to the interior side of exterior walls of masonry or concrete shall be isolated from the exterior wall.

1.2 Gypsum plasters shall not be used in exterior locations or interior “wet” areas.

NOTE 1: To secure desirable results, this specification should be coordinated with the provisions of Specification C841. General information concerning full thickness gypsum plastering is contained in Annex A2, Annex A3, and Annex A4.

1.3 Details of construction for a specific assembly to achieve the required fire resistance shall be obtained from reports of fire-resistance tests, engineering evaluations, or listings from recognized fire testing laboratories.

1.4 Details of construction to achieve required sound control shall be obtained from reports of tests conducted at recognized sound testing laboratories in accordance with the applicable sound tests of Test Methods E90, C423, or E492.

1.5 The values stated in inch-pound units are to be regarded as the standard. The SI (metric) values given in parentheses are approximate and are provided for information purposes only.

1.6 The text of this standard 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 standard.

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