A 40 Mil composite consisting of 35 Mils of self-adhering rubberized asphalt laminated to a 5 Mil woven polypropylene film. A siliconized one-piece release liner prevents the material from bonding to itself in the roll and is easily removed for installation. F5 Air & Vapor Barrier is available in a 325 sq. ft. roll with dimensions of 39"x 100'. The factory-controlled thickness of the membrane ensures uniform barrier properties, and the woven polypropylene film increases strength and has a non-skid surface suitable for the bonding of subsequent layers.