A Building Debate That Just Won’t Go Away
Poly sheeting installed behind drywall has been linked to mold and rot in numerous homes across the country. So why is it still popular with many builders and architects?
Over time, the use of polyethylene vapor barriers has been challenged by many building scientists. Yet some builders still use them, and some architects still believe they are appropriate.
Stephen Thompson is one of them. In a post to the Q&A forum at GreenBuildingAdvisor, the architect says 10 years of work in Minnesota has convinced him a poly vapor barrier is necessary. He also points out that experts conducting seminars at AIA conventions insist vapor barriers are “essential in cold climates.”
Thompson’s claims rekindles an old debate on whether poly vapor barriers are a help or hindrance, and whether the real danger to buidlings are air leaks, not vapor diffusion. The conversation is the focus of this week’s Q&A Spotlight.