RoofViews

Building Science FAQ — Ep. 4

By Don Kilcoyne

January 04, 2019

episode 4 of building science FAQs

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?

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About the Author

Don Kilcoyne
Don Kilcoyne

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This blog contains information created by a variety of sources, including internal and third party writers. The opinions and views expressed do not necessarily represent those of GAF. The content is for informational purposes only. It is not intended to constitute financial, accounting, tax, or legal advice, or professional design advice as to any particular project. GAF does not guarantee the accuracy, reliability, and completeness of the information. In no event shall GAF be held responsible or liable for errors or omissions in the content or for the results, damages or losses caused by or in connection with the use of or reliance on the content. Consult a design professional to ensure the suitability or code compliance of a particular roofing system for any particular structure.