House wrap is one of those materials that is invisible once the siding goes up, but it protects the most expensive thing you own from moisture damage. Getting the quantity right matters — running short mid-job means a trip to the supply house and potential delays, while overbuying ties up cash. Here is how to calculate exactly what you need.
| Measurement | Value |
|---|---|
| House dimensions | 50 ft × 30 ft (perimeter = 160 ft) |
| Wall height to eaves | 9 ft |
| Gross wall area | 160 × 9 = 1,440 sq ft |
| Windows (12 at 3×4 ft avg) | 12 × 12 = 144 sq ft |
| Doors (2 at 3×7 ft) | 2 × 21 = 42 sq ft |
| Net wall area | 1,440 − 186 = 1,254 sq ft |
| With 12% overlap | 1,254 × 1.12 = 1,404 sq ft |
| Rolls needed (1,350 sq ft/roll) | 1,404 / 1,350 = 1.04 → 2 rolls |
Two rolls with some left over for flashing details, patches, and mistakes. For a two-story home with the same footprint, double the wall height portion (wall area becomes approximately 2,880 sq ft gross) and plan for 3 rolls.
| Product | Roll Size | Cost/Roll | Cost/sq ft | Best For |
|---|---|---|---|---|
| Tyvek HomeWrap | 9′ × 150′ (1,350 sf) | $150–$200 | $0.11–$0.15 | Standard residential, most widely specified |
| Tyvek DrainWrap | 9′ × 100′ (900 sf) | $140–$180 | $0.16–$0.20 | Behind stucco, stone veneer (has drainage channels) |
| Tyvek CommercialWrap | 5′ × 200′ (1,000 sf) | $130–$170 | $0.13–$0.17 | Taller commercial walls |
| ZIP System sheathing | 4′ × 8′ panels | $25–$35/sheet | $0.78–$1.09 | Combined sheathing + WRB in one product |
| Typar HouseWrap | 9′ × 150′ (1,350 sf) | $100–$140 | $0.07–$0.10 | Budget alternative, woven polyethylene |
| Felt paper (15 lb) | 4′ × 144′ (576 sf) | $20–$30 | $0.03–$0.05 | Traditional method, still code-compliant |
This is where most moisture problems originate. The critical sequence:
Reservoir claddings (stucco, manufactured stone, adhered thin brick) hold moisture and can push it inward. You need either a drainage-type wrap (like Tyvek DrainWrap) or a separate drainage mat behind the wrap. Building codes increasingly require a minimum 1/16” drainage space behind reservoir claddings.
Standard cap staples may not hold in hurricane zones. Use 1” cap nails at 6” OC along studs, and consider a product with higher tear strength. Some codes in coastal areas require specific wind-driven rain resistance testing (ASTM E331).
Estimate your siding materials with our Siding Calculator and calculate insulation needs with the Insulation Calculator.
Yes. The IRC (International Residential Code) requires a weather-resistant barrier (WRB) behind all exterior claddings. House wrap, felt paper, or integrated sheathing systems (like ZIP) all satisfy this requirement. The specific product is your choice, but the WRB itself is mandatory.
You can, but it is generally unnecessary and may reduce the wall's drying potential. One properly installed layer with taped seams provides the required water resistance and vapor permeability. Double wrapping is sometimes done behind stucco as a belt-and-suspenders approach, but a single drainage-type wrap is the better solution.
Professional installation runs $0.50-$1.00 per sq ft of wall area including materials. For a typical home with 1,500 sq ft of wall, expect $750-$1,500 total. This is often included in the siding contractor's bid rather than quoted separately.
Both meet code requirements. Tyvek (HDPE flashspun) has higher vapor permeability (~58 perms vs ~12 perms for Typar), meaning it lets wall moisture escape more readily. Typar (woven polyethylene) is more puncture-resistant and costs less. For most residential applications, either works. Behind reservoir claddings, Tyvek's higher permeability is an advantage.
Either position can work, depending on your wall assembly design. WRB over foam (outboard) is simpler — you tape the foam seams and add house wrap as the drainage plane. WRB under foam works if the foam is taped and flashed to serve as the drainage plane. Consult your building science details for your specific climate zone.