Accuply Premium Plywood Underlayment has a rugged, solid core construction (5- or 7-ply) made from hard, relatively knot-free Baltic Birch grown in Northern European forests. It has more indentation resistance than poplar and luaun plywoods, to prevent crushing from from high-heeled shoes, table/chair legs, and moving appliances. This high quality plywood provides a stiffer, more structurally sound underlayment for vinyl, laminate, carpet, ceramic tile or wood floors. Eliminate imperfections in the subfloor with Premium Birch Underlayment for a smooth, defect-free surface.