Vapor Barrier Calculator
Vapor barrier is sold by the roll and every seam needs a 12-inch lap. This adds the overlap in so you don't come up short mid-job.
Your project
Your results
- Sheeting required
- 1,444 sq ft
- Strips across the space
- 3 runs
- Linear feet of roll
- 120 ft
- Seam tape needed
- 132 ft
- Wall run-up area
- 136 sq ft
- Material cost
- $232
Includes 15% for laps and trim
12 ft roll, 12 in overlap
Estimates use typical US material and labor pricing. Confirm quantities against the coverage chart on the bag before you buy.
Gear for this job
Vapor Barrier Plastic Sheeting
Plastic Sheeting (10' x 25') Long, 6 Mil - UV Protection Poly Sheeting Polyethylene Film, Heavy Duty Greenhouse Plastic Sheeting
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Frost King P1025/6W Polyethylene Sheeting, 10' x 25' x 6 mil., Clear
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Aluf Plastics 6 MIL Thick Extra Strong Heavy Duty Clear All Purpose Vapor and Moisture Barrier Sheet Tarp/Drop Cloth - 10' x 25' - for Painting, Furniture, Carpet, Contractor, & Construction
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House Wrap Insulation Tape
XFasten Foam Pipe Insulation Tape 2 Inch x 15 Feet Heavy-Duty AC Line Insulation Outdoor Pipe Wrap Tape AC Pipe Insulation Outdoor Pipe Insulation Wrap Tape HVAC Line Insulation Pipe Wrap Around Tape
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Vapor Barrier Tape 4" x180' 1 Roll Waterproof Seam Tape | White polyethylene tape for crawl spaces & moisture barriers, waterproof seam tape for underlayments, insulation & liners
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BlueTex Insulationㅤ 4'' Wide x 180' Long White Vapor Barrier Tape - 1 Roll, Waterproofing for Stucco, Crawlspaces, Repair, Underlayment Seams, Metal Building Seams, Excellent Air Barrier
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Foil Tape Hvac Insulation
Romeda Aluminum Foil Tape, 2 inch x 65 Feet Foil Tape (3.9 mil), Silver Insulation Adhesive Metal Tape, High Temperature Heavy Duty HVAC Tapes for Ductwork, Dryer Vent, HVAC
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Aluminum Foil Duct Tape Heavy Duty Waterproof, Premium Silver Metal HVAC Heat Tapes (2"*65Feet,3.9mil), High Temperature, Dryer Vent Insulation Tape for Ductwork, Ducting, Sealing, Patching, Furnace
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ETERART Aluminum Foil Duct Tape, High-Temp Seal for HVAC,2" x 20Yds | Heavy-Duty, Dryer Vents & Insulation, Stops Air Leaks & Resists Extreme Heat for Home Repair, Silver, easy to apply, durable
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How this calculator works
- Base area = (length × width) + wall run-up area
- Total sheeting = base area × 1.15 for laps and trim
- Runs = width ÷ (roll width − 1 ft overlap)
Frequently asked questions
How thick should a crawlspace vapor barrier be?
6 mil meets code for a vented crawlspace. For full encapsulation or if anyone will crawl on it, use 10 to 20 mil reinforced.
Which side does a vapor barrier go on?
Toward the warm side in winter — the interior in cold climates. In hot-humid climates skip the interior barrier entirely; it traps moisture on the wrong side.
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Sheeting required
1,444 sq ft