Every piece meets the highest grading standards for strength and appearance. This plywood combines sub floor and underlay into a single powerful panel for use under carpet and pad, hardwood flooring, or vinyl tile. Our specially designed smooth surface resists punch-through damage and is touch-sanded for uniform thickness. It wears well under high traffic and heavy furniture. Made of layers thin sheets of wood (veneer) in alternating wood grain directions, which increases strength and stiffness and minimizes floor bounce. Tongue and grooved edges eliminate blocking, provide proper spacing and simplify installation.