air retarder / barrier

An air retarder or barrier is a material or structural element that inhibits air flow into and out of a building's envelope or shell. This is a continuous sheet composed of polyethylene, polypropylene, or extruded polystyrene. The sheet is wrapped around the outside of a house during construction to reduce air infiltration and exfiltration, yet allow water to easily diffuse through it.


air retarder