Using Polyethylene as an Air Barriercomments (2) October 28th, 2011 in Blogs
Many builders have stopped using polyethylene vapor retarders, not only because they are no longer viewed as a necessity in most climates, but also because poly has the potential to trap moisture in walls and ceilings. Air barriers are now viewed as much more important.
More from greenbuildingadvisor.com
But a poster at GreenBuildingAdvisor's Q&A forum wonders whether poly might make a good air barrier in a high-performance building he's putting up. Minneapolis Disaster has read of successful uses of poly in well-insulated houses with extremely low rates of air infiltration. Plus, it comes in 12-ft. wide rolls that would be more convenient than housewrap, which comes in 10-ft. widths.
Minneapolis proposes to use a layer of poly on outside walls between plywood sheathing and a layer of polyisocyanurate foam insulation; in the ceiling, poly would fall between two layers of polyiso.
Is the plan risky?
That's the subject of this week's Q&A Spotlight.
posted in: Blogs, energy efficiency, insulation, water and moisture control
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