House Wrap Roll Calculator
Work out how many rolls of house wrap (weather-resistive barrier) your walls need from the gross wall area. Openings are covered by the wrap and then cut out, so nothing is subtracted — use the full wall area.
Calculator
Wrapping 1,410 sq ft of wall with 900 sq ft rolls takes 2 rolls — openings are usually left in (the wrap is cut out afterward), so use the gross wall area.
House wrap is the weather-resistive barrier that goes on the sheathing before siding: it sheds bulk water while letting vapor escape. Unlike the siding itself, wrap is installed over the whole wall, openings included — the installer wraps straight past each window and door, then cuts the opening out and folds the flaps in. That is why you size it from the gross wall area and never deduct openings.
Rolls come in a few standard sizes. A 9 ft × 100 ft roll is 900 sq ft and covers a typical single story in one horizontal band; there are also 3-, 5- and 10-ft-wide rolls. Divide the gross wall area by your roll’s coverage and round up.
Formula
One division, rounded up to whole rolls:
rolls = ⌈ gross wall area ÷ roll coverage ⌉
- gross wall area — the full wall and gable area, openings not deducted.
- roll coverage — the square feet a single roll covers (9 × 100 = 900 sq ft is common).
Worked example
For 1,410 sq ft of gross wall with 900 sq ft rolls:
- Rolls: 1,410 ÷ 900 = 1.57.
- Round up: 2 rolls.
Note the gross wall area here is the wall-plus-gable figure before subtracting openings — the same house that needed 1,230 sq ft of siding needs wrap for the full 1,410 sq ft, because the wrap covers the openings too.
Why openings stay in
Do not deduct openings. This is the one place in the siding take-off where you use the gross area, not the net. The wrap runs continuously across windows and doors and is trimmed afterward, so subtracting openings would leave you short.
Overlaps are built into the rounding. House wrap laps horizontally (upper course over lower, shingle-style) and vertically at seams, typically several inches. On a single-story wall a 9-ft roll usually covers the height in one pass with the lap to spare; taller walls take a second course. Rounding up to whole rolls absorbs the modest lap allowance for most houses, but on a large or tall building add a roll for generous seam overlaps.
Tape and fasteners are extra. Seam tape, flashing tape at openings and cap fasteners are ordered separately — the roll count only covers the field material. Follow the manufacturer’s installation instructions, as their warranty depends on correct overlaps, taping and integration with window flashing.
Frequently asked questions
How big is a roll of house wrap?
A very common size is 9 ft × 100 ft, which is 900 sq ft. Narrower 3-, 5- and wider 10-ft rolls are also sold. Enter your roll’s coverage so the count matches the product you are buying.
Do I subtract windows and doors for house wrap?
No. The wrap is installed over the entire wall, including openings, and then cut out at each window and door. Always size it from the gross wall area — deducting openings would leave you short of material.
How much house wrap do I need for 1,500 sq ft of wall?
With 900 sq ft rolls: 1,500 ÷ 900 = 1.67, which rounds up to 2 rolls. On a tall or complex wall with many seams, consider a third roll to keep generous overlaps.
Does the roll count include overlaps?
Rounding up to whole rolls absorbs the modest horizontal and vertical laps on a typical single-story house. For large or tall buildings with many seams, add a roll to be safe, since laps of several inches add up across a big elevation.
Is seam tape included in the roll count?
No — seam tape, flashing tape at openings and cap fasteners are separate items. The roll count covers only the field wrap; buy tape and fasteners per the manufacturer’s instructions.