- Wall area— sq ft
- Adjusted area— sq ft
- Roll size—
- Estimated cost—
Shopping Summary
| Wall area | — |
| Overlap + waste adjusted | — |
| Roll size / coverage | — |
| Rolls to buy | — |
| Estimated cost | — |
Roll Coverage Chart
| Roll size | Coverage |
|---|---|
| 3 ft x 100 ft | 300 sq ft |
| 9 ft x 100 ft | 900 sq ft |
| 9 ft x 150 ft | 1,350 sq ft |
| 10 ft x 100 ft | 1,000 sq ft |
The tall 9 and 10 ft rolls cover a full wall height in one pass, with fewer seams than 3 ft rolls.
How Much House Wrap Do I Need?
House wrap is sold in rolls, so the real answer is how many rolls to buy, not a raw square footage. Start from your total exterior wall area, either entered directly or from the house length, width, and wall height, then add for the overlap at every seam and a waste factor for cuts and corners. Divide that adjusted area by the coverage of one roll and round up. This calculator does all of that and gives you a roll count, so you leave the store with enough wrap instead of a number that needs translating in the parking lot.
House Wrap Overlap Guide
Overlap is what makes the wrap shed water. Horizontal seams, where one course laps over the one below, should overlap about 6 inches so water always runs over the joint, not into it. Vertical end laps where rolls meet should overlap about 12 inches and land over a stud. Around corners, wrap past the edge at least 6 to 12 inches and lap the next wall over it. Those overlaps add up, which is why this calculator pads the wall area before counting rolls; skipping the allowance is how people end up one roll short.
House Wrap vs Felt vs Building Paper
All three are water-resistive barriers that go behind siding, but they differ. Asphalt felt, the old standby, is heavy, tears easily, and can wrinkle, but it is cheap and breathable. Building paper, like Grade D kraft paper, is common behind stucco. Modern plastic house wrap is lighter, comes in wide rolls that install fast with fewer seams, resists tears, and blocks air infiltration while letting vapor escape. House wrap is the usual choice for new framing and re-siding; felt and building paper still appear in specific assemblies and stucco work.
Frequently Asked Questions
Do I deduct windows and doors? You can, but many installers wrap over openings and cut them out, so deducting is optional; leaving them in adds a small safety margin.
Which way does the overlap go? Upper pieces always lap over lower pieces so water sheds outward and down.
How many rolls for an average house? A typical single-story home runs two to three 9 ft rolls; a two-story home, three to five.
Can house wrap be left exposed? Only briefly. Most wraps allow a few months of UV exposure before siding must go on; check the brand.