Perm-A-Barrier VPL is a fire-resistive, one component, fluid-applied vapor permeable air barrier membrane that protects building envelope from air leakage and rain penetration, but allow the walls to "breathe". Perm-A-Barrier VPL is plasticizer-free, phthalate-free and halogen-free, providing safe and environmentally friendly air barrier application. Perm-A-Barrier VPL has been evaluated within various wall assemblies with or without foam plastic insulation.

Perm-A-Barrier VPL membrane provides superior protection against the damaging effects of air and liquid water ingress on building structures. The product creates a solid barrier against air infiltration and exfiltration, which minimizes associated energy loss and condensation problems. As a vapor permeable membrane, it permits the transfusion of water vapor that may otherwise condense in the wall structure; but is impermeable to liquid water, which allows the material to act as a water drainage plain.