USG Durock™ Brand Glass-Mat Tile Backerboard is a moisture- and mold-resistant gypsum panel with a fiberglass mat facer and back. The face of the panel is treated with a patented cementitious coating for moisture resistance and enhanced tile bond, making it ideal as a tile substrate for wet areas Res1, Res2, Res3, Com1, Com2 and Com3 as defined by the Tile Council of North America Handbook 2014. USG Durock™ Glass-Mat Tile Backerboard combines the tile bond of cement board with the handling and ease of use of a USG Sheetrock® Brand panel. The 5/8" Type X panels are UL classified as fire resistant.