House Wrap Calculator
Estimate whole house-wrap rolls from gross exterior wall area, roll size, overlap, detailing and waste.
Estimate house wrap or another sheet water-resistive barrier from simple building dimensions or a known gross wall area. The calculator includes triangular gables, project-specific overlap and detailing allowance, separate waste, whole-roll rounding and optional user-entered tape, fastening and pricing information. It intentionally does not subtract windows and doors automatically because wrap is commonly installed across openings and cut during the flashing sequence. Confirm that method, all laps and every accessory with current instructions for the exact selected system.
Gross Exterior Wall Area
This calculator intentionally uses gross wall area without automatically subtracting windows or doors. House wrap is often installed across openings and cut during flashing, but layouts and current manufacturer instructions vary.
House-Wrap Roll and Allowances
Use the exact roll dimensions and installation requirements for the selected water-resistive barrier. Nominal roll area does not account for course laps, corners, openings, flashing integration or damaged material.
Optional Tape and Fastener Estimate
Enter tape and fastening quantities only from a project-specific layout and approved installation instructions. Leave any group blank to omit it.
Your Estimate
Rectangular Wall Area
1400.00 sq ft
Gable Area
180.00 sq ft
Gross Wall Area
1580.00 sq ft
After Overlap & Detailing (10%)
1738.00 sq ft
Total Order Area (5% waste)
1824.90 sq ft
Nominal Coverage per Roll
900.00 sq ft
House-Wrap Rolls to Buy
3 rolls
Uses gross wall area, adds 10% for overlaps and detailing, then 5% waste. Purchasing quantities round up to whole units. Nominal roll area is not guaranteed installed coverage.
Results Actions
This calculator provides a preliminary water-resistive-barrier material estimate only. It does not select or design a wall assembly; determine vapor permeability, drainage, flashing, fastening, wind, fire or code requirements; inspect sheathing or concealed moisture damage; or replace current manufacturer instructions. Exterior work involves serious fall, ladder, scaffold, electrical, cutting, overhead and weather hazards. Have qualified building-envelope and construction professionals confirm the product, assembly, flashing sequence, fastening and final quantities before ordering or installation.
House Wrap Measurement and Roll Reference
Listed roll sizes are editable calculation examples, not product recommendations. Availability, actual dimensions, permitted exposure, laps, fastening, seam treatment and published coverage differ by product, wall assembly and market.
How to Use the House Wrap Calculator
- 1Choose Imperial or Metric measurements.
- 2Enter simple rectangular-building dimensions and matching gables, or enter a measured gross exterior-wall area.
- 3Keep openings in the gross area unless current product instructions and the planned installation method support a different takeoff.
- 4Choose a listed roll or enter the exact custom roll width and length shown for the selected product.
- 5Choose separate overlap/detailing and waste allowances appropriate to the wall layout and installation instructions.
- 6Optionally enter a project-specific tape length and the published usable length per tape roll.
- 7Optionally enter a confirmed total fastening run and approved spacing; the calculator will not choose a fastening schedule.
- 8Enter available unit prices, then review whole rolls, optional accessories and the partial material-cost estimate before ordering.
House Wrap Roll, Tape and Fastener Formulas
- 1Rectangular wall area = 2 × (building length + building width) × rectangular wall height.
- 2Total gable area = number of matching gables × gable base width × gable rise ÷ 2.
- 3Gross wall area = rectangular wall area + total gable area.
- 4Nominal roll area = roll width × roll length.
- 5Overlap-adjusted area = gross wall area × (1 + overlap and detailing percentage ÷ 100).
- 6Total order area = overlap-adjusted area × (1 + waste percentage ÷ 100).
- 7House-wrap rolls = total order area ÷ nominal roll area, rounded up to whole rolls.
- 8Optional tape rolls = entered tape length ÷ published usable tape length per roll, rounded up.
- 9Optional fasteners = entered total fastening run ÷ entered approved spacing + one endpoint fastener, rounded up.
- 10Optional fastener boxes = total fasteners ÷ entered fasteners per box, rounded up.
- 11Estimated entered material cost = whole wrap rolls × price per roll + whole tape rolls × tape-roll price + whole fastener boxes × box price. Blank items are omitted.
Imperial and Metric House Wrap Examples
Imperial example: a 40 ft × 30 ft rectangular building with 10 ft walls has 1,400 sq ft of rectangular wall area. Two 30 ft-wide gables rising 6 ft add 180 sq ft, for 1,580 sq ft gross. Adding 10% for overlaps and detailing gives 1,738 sq ft; adding 5% waste gives 1,824.90 sq ft. A 9 ft × 100 ft roll has 900 sq ft of nominal area, so divide 1,824.90 by 900 and round up to 3 rolls. Metric example: 142.2 m² gross with 10% overlap/detailing and 5% waste becomes 164.24 m². A 2.7 m × 30 m roll has 81 m² nominal area, so the preliminary quantity is 3 rolls. Both examples are arithmetic demonstrations; actual installed coverage and accessories require product-specific layout and instructions.
Accuracy & Assumptions
- All wall and gable surfaces in scope are represented by the entered gross area or simple-building dimensions.
- Gross area retains openings unless the selected system and installation sequence support a different takeoff.
- Roll width and length match the exact purchasable product and the nominal coverage basis used for planning.
- Overlap and detailing allowance represents expected course laps, vertical joints, corners and opening work only as a preliminary percentage.
- Waste is applied once after the overlap/detailing allowance and before whole rolls round up.
- The estimate does not optimize individual roll starts, remnants or reusable offcuts.
- Entered tape length and coverage use the same units and represent the usable installed length of the selected tape.
- Entered fastening run and spacing come from an approved product-specific layout and use consistent units.
- Optional prices use the same roll or box basis as the displayed quantities and one consistent currency.
- Qualified professionals will confirm wall assembly, drainage, flashing, fastening, exposure, fire, wind and code requirements separately.
Frequently Asked Questions
How do I calculate how much house wrap I need?
Calculate gross exterior wall and gable area, add allowances for required laps and detailing, add project waste, divide by the selected roll’s nominal area and round up.
Should I subtract windows and doors from house-wrap area?
Not automatically. Wrap is commonly run across openings and cut during the flashing sequence, so gross area is often the safer planning basis. Follow the exact system instructions and project layout.
How many square feet are in a roll of house wrap?
Multiply roll width by roll length. A 9 ft × 100 ft roll has 900 sq ft of nominal area, before overlaps, corners, openings, detailing and waste.
Is nominal roll area the same as installed coverage?
No. Required course laps, vertical joints, corners, penetrations, opening details and damaged material reduce practical coverage.
How much overlap should I allow?
Required horizontal and vertical laps vary by product, wall assembly, opening detail and exposure. Use current manufacturer instructions; the percentage field is only a planning allowance.
How much waste should I add for house wrap?
Waste depends on wall lengths, roll width, gables, corners, openings, wind and handling. Five or ten percent may be useful for early planning, but a roll layout and supplier guidance are more reliable.
Does the calculator estimate tape?
Yes, when you enter the required tape length and the selected tape roll’s published usable coverage. It does not determine which seams or flashing details require tape.
Does the calculator estimate cap fasteners or staples?
Only when you enter a confirmed fastening run and approved spacing. It does not choose fastener type, spacing, pattern, substrate attachment or wind requirements.
Is house wrap waterproof?
House wrap is generally part of a water-resistive and drainage assembly, not finished waterproof cladding. Performance depends on correct laps, flashing, penetrations, transitions and siding installation.
Is house wrap a vapor barrier?
Do not assume it is. Products have different vapor-permeance characteristics, and wall assemblies require climate- and code-appropriate moisture design.
Do I need house wrap behind siding?
Required water-resistive barriers and drainage details depend on locally adopted code, the cladding, sheathing, climate, wall assembly and approved product instructions. Confirm the project requirements.
Can I use this calculator for different building-wrap brands?
Yes for preliminary quantity planning when you enter the exact roll dimensions and allowances for the selected system. The calculator does not select or approve a product.
Can I estimate material cost?
Yes. Enter current prices for wrap rolls and any calculated tape or fastener boxes. The estimate excludes labor, tax, delivery and unlisted materials.
Can I use Metric measurements?
Yes. Metric mode uses m and m² with native example roll dimensions. Replace the examples with exact products available in the project market.
This calculator provides a preliminary house-wrap or water-resistive-barrier quantity estimate only. It does not select or design a wall assembly; determine product suitability, vapor permeability, drainage, flashing, window or door integration, fastening, wind resistance, fire performance, structural attachment or code compliance; inspect sheathing or concealed moisture damage; or replace approved plans and current manufacturer instructions. Product sizes, laps, coverage, seam treatment and accessory requirements vary. Exterior work involves serious fall, ladder, scaffold, electrical, cutting, overhead and weather hazards. Follow applicable requirements and current instructions for the complete selected system, and have qualified building-envelope and construction professionals confirm the assembly, substrate, flashing sequence, fastening, measurements and final quantities before ordering or installation.