GlasRoc Tile Backer is a gypsum tile substrate panel for walls and ceilings, specially formulated with a water-resistant core to meet the demands of high-moisture areas. For greater convenience, GlasRoc Tile Backer allows you to apply tile using thinset or mastic compounds.Valued for its mold resistance, it is well-suited for tile and non-tile installations in wet and non-wet applications, and in areas of high humidity. It also offers excellent fire-resistance properties, and can be used in numerous fire-rated designs and assemblies.