Air Barrier vs. Vapor Retarder
Welcome to Episode 4 of The Building Science FAQ series.
The Building Science FAQ video series explores some of the technical questions that crop up when specifying a low-slope roof.
In this episode, Jennifer Keegan, director of building and roof science, GAF, and Jim Kirby, GAF building and roofing science architect, address a common area of confusion: "What is the difference between an air barrier and a vapor retarder?" While an air barrier stops air leakage, a vapor retarder reduces moisture diffusion to reduce the risk of condensation forming in the roof assembly. But can an air barrier be a vapor retarder?
- Episode 1: How Strong is a Thermoplastic Weld?
- Episode 2: How Chemical Resistant are TPO and PVC?
- Episode 3: What is a roof coating?
- Episode 5: What is the difference between a metal roof and a metal deck?