Calculate house wrap (weather barrier) rolls needed for exterior walls. Estimates from gross wall area with overlap allowance for Tyvek, Typar, and similar products.
House wrap (weather-resistant barrier or WRB) is installed over the exterior sheathing and under the siding to prevent water infiltration while allowing water vapor to escape. Products like Tyvek HomeWrap, Typar HouseWrap, and ZIP System sheathing tape are common choices in residential construction.
This calculator determines how many rolls of house wrap are needed based on the gross wall area (not net — house wrap covers the entire wall surface, including behind windows and doors, since it's part of the waterproofing system). It adds overlap allowance because house wrap must overlap 6–12 inches at horizontal seams and 6 inches at vertical seams.
House wrap is typically sold in 9-foot by 100-foot or 9-foot by 150-foot rolls. The overlap requirement means actual coverage per roll is 10–15% less than the roll's nominal area.
Accurate calculation of this value helps construction professionals plan projects more effectively, reduce material waste, and ensure compliance with building codes and industry standards.
House wrap coverage is reduced by required overlaps. This calculator accounts for the overlap loss to ensure you order enough rolls to cover all exterior walls without gaps in the weather barrier. Consistent use of this tool across projects builds a library of reference data that improves estimating accuracy over time and reduces reliance on individual experience alone.
Gross Wall Area = Perimeter × Wall Height Roll Coverage = Roll Width × Roll Length Effective Coverage = Roll Coverage × (1 − overlap%/100) Rolls = Gross Wall Area / Effective Coverage (round up)
Result: 2 rolls
Gross wall area = 160 × 9 = 1,440 sq ft. Roll coverage = 9 × 100 = 900 sq ft. Effective coverage = 900 × 0.88 = 792 sq ft. Rolls = 1,440 / 792 = 1.82 → 2 rolls.
Traditional building paper (#15 asphalt felt) was the original weather barrier. Modern house wraps offer advantages: lighter weight, better tear resistance, higher moisture vapor transmission, and faster installation (wider rolls mean fewer seams). However, some builders still prefer felt for its self-sealing properties around fastener holes.
Install house wrap after sheathing and before window/door flashing. Starting at the bottom, wrap horizontally around the house with each course overlapping the one below. At corners, continue the wrap around (don't terminate at corners). Tape all seams with manufacturer-specified tape. Then flash all openings, and finally install the siding.
ZIP System sheathing eliminates separate house wrap by integrating a moisture barrier directly into the OSB sheathing panel surface. Seams are sealed with ZIP System tape. This reduces labor (one less trade step) and eliminates the gap between sheathing and house wrap where wind-driven rain can enter. The trade-off is higher sheathing cost.
House wrap is installed over the entire wall including across window and door openings. After wrapping, you cut an X or I-shaped slit at each opening, fold the flaps inward, and flash the opening with self-adhering tape. This creates a continuous drainage plane around every opening.
Tyvek HomeWrap (DuPont) is a spunbonded polyethylene sheet with very high moisture vapor transmission. Typar (Berry Global) is a woven polypropylene that is more tear-resistant but slightly less vapor-permeable. Both meet code requirements. Tyvek is more widely specified by builders.
Minimum 6" horizontal overlap (bottom course under top course). Minimum 6" vertical overlap. Many builders use 12" horizontal overlap for better performance. At corners, wrap continuously around the corner by at least 12 inches.
For exterior foam board insulation: house wrap typically goes over the sheathing and under the foam, but some systems place it over the foam. Follow the specific product system's instructions. ZIP System eliminates separate house wrap by integrating the WRB into the sheathing panel.
No. House wrap is designed for vertical wall applications only. It does not have the water-holding capacity needed for roof applications. Use proper roofing underlayment (felt or synthetic) on the roof deck.
The IRC (International Residential Code) requires a weather-resistant barrier behind all exterior cladding. House wrap is the most common way to meet this requirement. Alternatives include building paper (#15 or #30 felt), fluid-applied barriers, and integrated sheathing systems like ZIP.