Mapeguard^® UM 35 [NA] is an uncoupling, crack-isolation, waterproofing and vapor-management membrane made from high-density polyethylene (HDPE) with a rough surface and polypropylene fabric backing. Mapeguard UM 35 [NA] is designed for installing ceramic and stone tile, including over existing non-cushioned resilient flooring, ceramic tile and stone tile. It is designed to perform over challenging substrates, such as young concrete and single-layer 3/4" (19 mm) plywood subfloors with joist spacing of up to 19.2" (49 cm) on center.