Housewrap is a weather-resistant membrane installed over building sheathing to block wind and water penetration while allowing water vapor to escape, protecting the building envelope and insulation. Common materials include spunbonded polypropylene with permeance ratings of 50 to 85 perms, balancing water resistance with vapor permeability. Housewrap is a critical component in modern building envelopes, reducing moisture damage and improving thermal performance.
Installation Standards
Housewrap installation requires 6-inch overlaps on seams with horizontal lap edges facing downward to shed water. Products must cover all exterior wall areas, with special attention at window and door openings where synthetic tape or caulk seals penetrations. Proper installation takes approximately 0.15 to 0.25 hours per 100 square feet, with material costs around $0.15 per square foot.
Performance and Code Compliance
Housewrap reduces air infiltration through sheathing by 30 to 50 percent when installed correctly. High-quality housewraps achieve ASTM E331 water resistance ratings while maintaining minimum 5-perm vapor transmission for climate zones 5 and colder. When combined with proper drainage planes and caulking, housewrap significantly extends sheathing lifespan and improves overall building envelope performance.