Even industry experts confuse air, vapor and water resistive barriers. Let’s define the terms:
resist air leakage and form a continuous plane around a building to prevent uncontrolled air movement in and out of the building envelope.
limit the amount of water vapor diffusion through the wall as a result of different vapor pressures. Vapor barriers still have to be continuously sealed, and free of holes.
Water Resistive Barriers
keep liquid water from entering the building enclosure. Combined with flashing and other materials, WRBs ensure that there is a completely sealed assembly to direct liquid water to the exterior.
Did you know a single material can function as all three?
However, some materials function only as a water resistive barrier and cannot be considered an air barrier. CCW experts have created an e-booklet to help you understand the differences.
to download your copy of "Introduction to Water Resistive Barriers (WRBs) & Air Barriers."