Vapor Barrier Calculator
Calculate vapor barrier sheeting needed for crawl spaces, under slabs, and on walls. Includes overlap and seam tape quantities.
๐ก๏ธ Vapor Barrier Calculator
Results
Floor Area300.00 sq ft
Strips Needed2 strips
Rolls Needed1 rolls
Seam Tape20.00 lin ft
๐ก How to Calculate Vapor Barrier Material
Vapor barriers are polyethylene sheeting (typically 6โ20 mil thick) installed to prevent moisture migration. For crawl spaces, cover the entire floor and run 6 inches up the walls. For under-slab applications, use 10-mil or thicker.
Seams must overlap 6โ12 inches and be sealed with vapor barrier tape. Calculate strips by dividing the width of the area by the effective roll width (roll width minus overlap). Standard roll sizes: 10 ft, 12 ft, or 20 ft wide ร 100 ft long.
A 20ร15 ft crawl space with 10 ft rolls and 12-inch overlap: effective width = 9 ft. Strips needed: 2. Material = 40 lin ft. 1 roll (10ร100 ft) is sufficient. Seam tape: 20 lin ft.