ASTM C842-05 (R2021) PDF Download

ASTM C842-05 (R2021) is a standard specification that outlines the minimum requirements for the application of interior gypsum plaster. The standard applies to various base materials such as gypsum, metal, masonry, or monolithic concrete, which are designed or prepared to receive gypsum plaster.

The specification specifies that gypsum plaster applied to the interior side of exterior walls of masonry or concrete must be isolated from the exterior wall. It also states that gypsum plasters should not be used in exterior locations or interior wet areas.

The standard provides detailed guidelines for surface preparation of plasters and emphasizes the importance of keeping plasters and cementitious materials dry until use. Storage of these materials should be done off the ground, under cover, and away from walls with condensation or other damp surfaces. Metal products should be protected against rusting while stored.

ASTM C842-05 (R2021) recommends mechanical mixing of plasters, although hand mixing is allowed if specified. The standard also allows for the application of plaster by both hand or machine, depending on the specific requirements.

It should be noted that this standard references notes and footnotes, which provide explanatory material but should not be considered as requirements of the standard. Additionally, to achieve the desired fire resistance and sound control, construction details should be obtained from reports of tests conducted at recognized fire testing laboratories and sound testing laboratories, respectively.