Project inputs
The calculator uses a responsive grid: 3 columns on large screens, 2 on smaller screens, and 1 on mobile.
Example data table
| Scenario | Perimeter | Wall Height | Stories | Openings Area | Roll Size | Waste | Estimated Rolls |
|---|---|---|---|---|---|---|---|
| Single-story home | 160 ft | 9 ft | 1 | 168 ft² | 9 ft × 100 ft | 10% | 4 |
| Two-story townhouse | 132 ft | 9 ft | 2 | 220 ft² | 10 ft × 100 ft | 12% | 5 |
| Garage addition | 84 ft | 10 ft | 1 | 72 ft² | 9 ft × 100 ft | 8% | 2 |
Formula used
The calculator estimates installed housewrap demand using wall geometry, deductions, overlap adjustments, seam loss, waste, and reserve ordering logic.
- Base wall area = perimeter × wall height × stories
- Gable area = gable count × (gable base × gable rise ÷ 2)
- Gross project area = base wall area + gable area + extra wall area
- Openings area = opening count × average opening width × average opening height
- Net cover area = gross project area − (openings area × opening deduction percentage)
- Usable roll coverage = roll width × roll length × overlap factor × seam factor
- Overlap factor = (roll width − horizontal overlap) ÷ roll width
- Seam factor = 1 − vertical seam loss percentage
- Required coverage = net cover area × (1 + waste percentage)
- Rolls to order = ceiling(required coverage ÷ usable roll coverage) + reserve rolls
How to use this calculator
- Choose feet or meters so all entered dimensions stay consistent.
- Enter building perimeter, wall height, story count, and any gable dimensions.
- Add extra wall area for dormers, bump-outs, parapets, or unusual surfaces.
- Enter opening counts and average sizes, then decide how much opening area to deduct.
- Enter the roll width, roll length, overlaps, seam loss, waste, reserve, and cost assumptions.
- Submit the form to see rolls required, usable coverage, fastener estimate, graph, and downloadable report options.
Frequently asked questions
1) Should windows and doors be deducted fully?
Usually no. Installers often cut, fold, flash, and wrap around openings, so a partial deduction is safer. Use the opening deduction percentage to match your field practice.
2) What overlap should I enter?
Use your project specification or manufacturer guidance. Many crews use several inches of horizontal lap. Enter the actual overlap planned on site for better coverage estimates.
3) Can this calculator work for wraps besides Tyvek?
Yes. The math is generic. Change the roll width, roll length, overlap, waste, and seam loss inputs to match the other product’s installation details.
4) Why is waste allowance important?
Waste covers cuts, damaged edges, starter strips, awkward corners, changes in layout, and crew handling losses. Without it, material orders are often too tight.
5) Why add reserve rolls if waste is already included?
Waste handles normal installation losses. Reserve rolls protect the schedule when weather, damage, design changes, or delivery delays create unexpected extra demand.
6) Is seam loss percentage exact?
No. It is a planning allowance. Real seam loss depends on wall lengths, roll layout, crew habits, and cut sequencing. Use field history for the best estimate.
7) Does the calculator support metric projects?
Yes. Switch to meters and keep every dimension in meters. The calculator will then report all coverage figures in square meters.
8) Does this include tape, flashing, or accessories?
No. This page focuses on wrap rolls, reserve, cost, and fastener estimates. Tape, flashing, sealants, and other accessories should be planned separately.