Easy-to-install Delta Floor Membrane is the perfect plastic subfloor system for concrete and slab on grade floors. This air-gap membrane is made up of a special high-density polyethylene resin (FDA approved), providing a dimpled surface with outstanding compressive strength, impact resistance and long-term performance. It is a uniquely dimpled, heavy-duty grey plastic membrane that keeps you and your family warm and comfortable in your basement, or any room in the house with a concrete, slab-on-grade floor. The membrane is installed with its dimples down to create a 5/16-inch thick air space above the slab, and can be covered with a plywood subfloor and topped off with carpet or flooring systems. Tape seams together using Delta tape: HH #2648-100. A 4 ft x 8 ft roll: HH #2648-102 and 3' 6" x 30' roll: HH #2648-105 are also available.