Choosing the right house wrap for your home is an important decision that will impact the long-term performance and durability of your exterior walls. House wraps, also known as weather-resistive barriers, are essential for controlling air infiltration and moisture intrusion in wall assemblies. With the wide variety of house wrap products on the market, it can be tricky to select the ideal one for your specific needs and climate. This comprehensive guide will walk you through the key factors to consider when choosing house wrap, so you can make an informed decision.
Types of House Wraps
There are several main categories of house wraps to choose from:
Asphalt-Saturated Kraft Paper
Asphalt-saturated kraft paper has been used as a house wrap for decades. It consists of two layers of kraft paper bonded together with asphalt. The asphalt coating makes it water-resistant while still allowing water vapor to pass through. Asphalt paper is inexpensive but less durable than other house wrap options.
Spunbonded Polyolefin
Spunbonded polyolefin, such as Tyvek, is made from polyethylene fibers which are pressed together to form a sheet. The fibers bond to create a material that blocks liquid water while allowing water vapor to diffuse. Spunbonded polyolefin is lightweight, water-resistant, and breathable. It is one of the most popular types of house wraps.
Spunbonded Polypropylene
Similar to spunbonded polyolefin, spunbonded polypropylene starts with polypropylene fibers which are pressed and bonded into sheets. The material resists liquid water while remaining permeable to water vapor. Spunbonded polypropylene is an economical option but not as robust as some other house wraps.
Perforated Films
Some house wraps use a micro-perforated plastic film as the water-resistive material. The small perforations allow water vapor transmission while the plastic film acts as a liquid water barrier. Perforated films can be made from various plastics including polypropylene.
High-Performance Composites
Advanced composites combine different materials to optimize house wrap performance. Some composites join spunbonded fabrics with perforated films. Others laminate polymers between non-woven fabrics. High-performance composites provide enhanced moisture control and durability.
Key Factors for Choosing House Wrap
With an overview of the main types of house wrap materials, we can now dive into the crucial factors to weigh when selecting your house wrap:
Water and Air Resistance
The primary job of any house wrap is resisting liquid water intrusion while allowing water vapor diffusion. Look for a product rated as W1 under the Water Resistance Test in ASTM E2556. This means it provides a water resistance of 55 cm or higher.
Air resistance is also important. The air infiltration rate should meet ASTM E2178 at a minimum of < 0.02 L/s/m2. Lower numbers indicate better air blocking.
Vapor Permeability
While blocking liquid water, house wraps need to let water vapor pass through. Look for wraps with a vapor permeance rating of at least 15 perms based on ASTM E96. The higher the perm rating, the more breathable the material.
Consider your climate when evaluating vapor permeability. In hot, humid climates, higher breathability is ideal. In cold climates, lower perms may be preferable.
Tensile Strength
The strength of the house wrap impacts its durability and wind resistance. Look for a product rated at least 30 lbs/in based on ASTM D882 for tear strength. Higher is better for longevity and resilience.
Air and Weather Barrier Continuity
A continuous air and weather barrier is crucial for performance. Make sure to choose a house wrap that fully seals seams, edges, fasteners, and penetrations. Many wraps have built-in adhesive strips to seal seams. Use manufacturer recommended tapes as needed.
UV and Chemical Resistance
House wraps need to hold up under ultraviolet light, pollution, and other environmental factors. Look for materials rated for at least 6 months of UV resistance. Check chemical resistance as well.
Flame Spread and Smoke Development
Safety is also important. Select a house wrap that meets code requirements for surface burning characteristics. Most wraps should have a flame spread of 25 or less and smoke development of 450 or less based on ASTM E84.
Cost
House wrap prices range widely from $0.10 per square foot on the low end to over $1 per square foot for premium products. Compare cost balanced with performance to find the right value for your project.
Manufacturer Warranty
A strong manufacturer warranty provides extra assurance of longevity. Many companies offer 10 year or 20 year limited material warranties. Read warranty details carefully and make sure the product is installed per guidelines.
Sustainability
For environmentally-friendly construction, look for house wraps made with recycled materials and recyclable at end of life. Some wraps utilize bio-based content instead of petroleum-derived chemicals. Check for certifications like UL EcoLogo.
Where to Use Different Types of House Wrap
Now that we’ve covered the key selection criteria, it’s helpful to summarize where to use the different categories of house wrap:
- Asphalt-saturated kraft paper works best as an economical option in milder climates without extreme weather. Avoid in very hot or wet environments.
- Spunbonded polyolefin wraps like Tyvek offer excellent value for most climates. The permeability and strength make them ideal for a wide range of homes.
- Spunbonded polypropylene can be a cheaper alternative to polyolefin wraps. Use caution in wet climates or on exposed walls.
- Perforated films work well as insect barriers and offer very high air resistance. Select ones with adequate vapor permeability for your climate.
- High performance composites provide maximum durability and moisture control in the most demanding climates with driving rain or tropical conditions.
Within each category, compare specific products to choose the ideal balance of performance, cost, and sustainability for your project.
House Wrap Recommendations by Climate
Here are some general recommendations for selecting house wrap materials based on your regional climate:
Hot, Humid Climates
In hot, humid southern regions with heavy rains, prioritize breathability along with moisture resistance. Look for wraps with a vapor perm rating of 30 perms or higher. Spunbonded polyolefin or composites work well.
Recommended products include:
- DuPont Tyvek HomeWrap
- KPTI RhinoRoof Underlayment
- Owens Corning Petro Vapor Perm
Cold, Snowy Climates
For cold northern regions, the optimal balance is enough vapor permeability combined with maximum air resistance. Aim for around 20 perms rating. Fiber-reinforced wraps are a smart choice.
Recommended cold climate house wraps:
- Dow Weathermate Plus
- GCP Applied Technologies WeatherWatch Plus
- Huber Zip System Sheathing
Coastal Regions
In coastal zones with high winds and salt spray, prioritize durability and seam strength. Look for tear resistance of at least 40 lbs/in. Woven polyolefin wraps work well near the ocean.
Quality coastal house wrap options:
- Atlas Resistance WR-2500
- DuPont Tyvek CommercialWrap D
- Green Guard Ultra Wrap
Arid, Desert Climates
In hot, dry regions, breathability is less critical than durability and UV resistance. Look for a Perm rating around 5 and 6-12 months of UV resistance. Spunbonded polypropylene wraps are suitable.
Good house wraps for desert climates:
- Alpha Pro Tech Guardian
- Fi-Foil Company Aluma WRAP
- OSI Quad Max
Mixed or Variable Climates
In regions with a wide range of weather patterns, a mid-range vapor permeable house wrap with good moisture resistance provides the most versatility. Spunbonded polyolefin is a common choice.
Quality all-purpose house wraps:
- Dow Weathermate Slate Gray
- FK Union Wrapping Paper VY-Duplex UV2
- ProVia StormWrap Advanced
Special Conditions to Consider
In addition to climate, also factor in any special conditions that may impact house wrap selection:
- Fire prone areas – Use wraps meeting WFCA no-burn standards like DuPont Tyvek CommercialWrap.
- High winds – Select durable wraps with tear resistance above 45 lbs/in like Alpha ProTech Fortress Pro.
- Rain screens – Ensure wrap has very high vapor permeability, at least 35 perms.
- Radon gas – Choose products meeting ASTM E2133 for radon resistance like RHH Radon Block.
- Pests – For termite/insect resistance, opt for a non-nutritive wrap like Vydax Insect and Termite Barrier.
House Wrap Installation Tips
Proper installation is just as crucial as the type of house wrap. Follow manufacturer guidelines closely. Key tips include:
- Install on exterior side of walls before windows, doors, siding.
- Orient horizontally with upper sheets overlapping lower sheets.
- Overlap seams at least 6 inches and tape tightly.
- Tape all joints, seams, tears immediately to maintain barrier.
- Seal carefully around openings like windows.
- Work cleanly and avoid punctures/tears in wrap material.
- Follow all manufacturer instructions for fastening, taping, flashing.
With quality materials and professional installation, a high performance house wrap will help manage moisture and improve the longevity of your home’s exterior walls. Carefully compare the available options using the criteria in this guide to select the ideal product for your climate and construction needs. Partnering with an experienced builder is also recommended to ensure proper house wrap application. Investing in the right weather barrier system will pay dividends through enhanced durability and reduced maintenance costs for years to come.
Frequently Asked Questions About Choosing House Wrap
Here are answers to some of the most common questions about selecting and using house wraps:
How to Choose House Wrap?
Consider the climate, exposure, lifespan, and hazards like fire when selecting house wrap. Compare materials based on water resistance, vapor permeability, tear strength, air barrier performance, and warranties. Spunbonded polyolefin is suitable for many climates while composites work well in demanding exposure.
What is the Best House Wrap?
The “best” house wrap depends on the specific conditions and desired performance. Top products like DuPont Tyvek and GCP WeatherWatch Plus offer a great combination of breathability, weather resistance, and durability. For budget projects, asphalt-saturated paper is a low-cost option.
Should House Wrap Touch Siding?
No. A proper drainage gap of at least 1/4 inch should be left between the house wrap and exterior siding/finishes. The gap allows drainage and ventilation to prevent moisture issues. Use spacers or furring strips to maintain the gap.
How Long Can House Wrap Be Exposed?
House wrap should not remain uncovered more than 4 months according to most manufacturer warranties. Prolonged UV and weather exposure will compromise the wrap’s performance. Install siding over the wrap as soon as possible.
Can House Wrap Be Stapled?
Yes, but nails or plastic cap staples are preferred. The cap fits over the staple leg to provide greater holding power. Staples should be at least 18 gauge with 1 inch plastic caps. Follow manufacturer specifications for approved fasteners.
What is Grade D House Wrap?
Grade D building wraps provide the highest level of performance. They have the tightest tear strength, tensile strength, air resistance and vapor perm ratings according to ASTM E1677. Grade D wraps are ideal for the most demanding climates.
Can House Wrap be Recycled?
Some house wraps like DuPont Tyvek can be recycled through manufacturer take-back programs. Other synthetic wraps may be recyclable through plastic recycling programs. Check with your installer for recycling options or for full-service wrap removal.
Does House Wrap Need Flashing?
Yes, flashing should be integrated with the house wrap system around all openings, protrusions and transitions to provide a continuous moisture barrier. Use compatible, high quality flashing materials approved by the wrap manufacturer.
How Long Does House Wrap Last?
With proper installation, quality house wraps can last 20-30 years or more before needing replacement. Factors likeunwrap exposure time, climate and materials impact lifespan. Inspect wrap periodically and rewrap if needed.
Conclusion
Choosing the optimal house wrap involves evaluating your climate, construction plans, and desired performance. Look for the right balance of air and water resistance, vapor permeability, strength, and durability while following manufacturer specifications. Investing in a quality wrap like Tyvek or WeatherWatch Plus and integrating it with a meticulous air sealing and flashing strategy will maximize your home’s resilience to moisture damage and air leakage over the long term. With this helpful guide, you now have an in-depth understanding of the critical factors for selecting the ideal house wrap.