Mapeguard Board is a multipurpose, premium-performance, lightweight, rigid, waterproof backer-board panel that is made with a high-density, extruded polystyrene core. This backer board features a high-strength, waterproof membrane and facer on both sides to provide water and vapor protection. Mapeguard Board is for use under ceramic tile and stone installations for both residential and commercial interior applications. The uniquely engineered, multi-layered design is available in thicknesses from 1/4" to 2" (6 mm to 5 cm) for use on walls, floors, ceilings and countertops, as well as for fabrication of room partitions, benches, seats and furnishing elements, delivering a dimensionally stable substrate.