The USG Durock™ shower trays, curb and benches are made of 3-pound density expanded polystyrene (EPS), offering greater support for the tile covering in shower applications. And because the shower trays are only 1" thick at the perimeter, barrier-free installations are much easier to construct without unwanted or unnecessary buildup of the surrounding subfloor. All it takes is just a few simple adaptations to wood-framed construction.