This specification covers coated glass mat water-resistant gypsum backing panel designed for use on ceilings and walls in bath and shower areas as a base for the application of ceramic or plastic tile. Coated glass mat water-resistant gypsum backing panel shall consist of a noncombustible water-resistant gypsum core, surfaced with glass mat, partially or completely embedded in the core, and with a water-resistant coating on one surface. The specimens shall be tested for flexural strength, humidified deflection, core hardness, end hardness, edge hardness, nail pull resistance, water resistance, and surface water absorption. Coated glass mat water-resistant gypsum backing panel shall have surfaces true and free of imperfections that render the panel unfit for its designed use.

1.1 This specification covers coated glass mat water-resistant gypsum backing panel designed for use on ceilings and walls in bath and shower areas as a base for the application of ceramic or plastic tile.

1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. Within the text, the SI units are shown in brackets.

1.3 The text of this standard references notes and footnotes that provide explanatory material. These notes and footnotes (excluding those in tables and figures) shall not be considered as requirements of the standard.

1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.