Vapor Barrier Calculator
Calculate Vapor Barrier Materials
Estimate polyethylene sheeting and accessories
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Formula
Rolls = (Total Area x 1.15 overlap) / Roll Coverage (sq ft)
Frequently Asked Questions
How thick should a vapor barrier be?
Use 6 mil poly for basic wall applications, 10 mil under concrete slabs, and 12-20 mil for crawl space encapsulation. Thicker barriers are more puncture-resistant and durable.
Do I need a vapor barrier in my crawl space?
Yes, building codes in most regions require a vapor barrier on exposed earth in crawl spaces. A minimum 6 mil polyethylene sheet reduces moisture, prevents mold, and improves indoor air quality.
How much overlap for vapor barrier seams?
Overlap vapor barrier seams by at least 12 inches. Seal all seams with vapor barrier tape or butyl tape. For crawl spaces, extend the barrier up foundation walls at least 6 inches.
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