Perm-A-Barrier® Wall Membrane is a tough, self-adhering, self-healing waterproofing membrane for air and vapor barrier applications. Consisting of 36 mil. of rubberized asphalt integrally bonded to 4 mil 0.1mm (.004 in), high density cross laminated polyethylene film. Perm-A-Barrier® Wall Membrane, when combined with a structural substrate, produces a virtually impermeable air, vapor and water barrier on concrete, masonry, gypsum board and wood walls. It is designed to be a cost-effective system providing a continuous seal against air, vapor and moisture around the entire building.