With so many house wraps on the market today, how do contractors and building owners decide which is the best? Most house wraps are weather-resistant barriers (WRBs) that aim to prevent air and moisture infiltration to the wall system while protecting the sheathing.
In this post, we compared Barricade® Wrap Plus, Tyvek® HomeWrap®, HomeGuard® House Wrap, CertainTeed CertaWrap™, and the ZIP System®. There were several vital performance components we considered when comparing these house wraps. These elements included durability, water and air resistance, vapor permeability, and drainage.
Comparing House Wrap Durability
A durable house wrap can stand up to the handling and installing process without becoming damaged, which will lessen its water-resistance performance. Durability parameters include ultraviolet (UV) rating, tensile strength, and cold and surfactant resistance.
- UV rating is the length of time a wrap will maintain its integrity when exposed to the sun.
- ASTM D1117 measures tensile strength or tear resistance.
- Cold resistance test standard (Cold Mandrel Bend Test: AC38 Section 3.3.4) determines if the wrap will crack at low temperatures.
- Surfactant resistance is critical to the long-term durability of a house wrap. Surfactants are contaminants (like soap and oils), that reduce the surface tension of a liquid, stopping it from absorbing deeper into the house wrap product.
Comparing House Wrap Water Resistance
A crucial requirement of a house wrap is to keep water out of the wall assembly. The ICC-ES allows for three water-resistance testing standards; however, plastic wraps are permitted only to use the first two.
- Hydrostatic Pressure, the most rigid test, exerts tremendous pressures on a house wrap through a column of water (55 cm or greater). AATCC Test Method 127: Water Resistance Hydrostatic Pressure Test.
- Water Ponding evaluates a house wrap’s resistance to a “pond” of 1-inch water after two hours. CCMC 07102 (Section 6.4.5): Water-Ponding Test.
- The Boat Test for felt and paper wraps is the least rigorous standard. Because it is highly sensitive to humidity and vapor transfer, it does not work for plastic house wraps. ASTM D779: Standard Test Method for Water-Resistance of Paperboard, Paper, and Other Sheet Materials by the Dry Indicator Method.
Comparing House Wraps Air Resistance
A house wrap’s air resistance is a continuous system that stops the flow of air across the building envelope. Three tests determine the air resistance of house wraps.
- ASTM E2178: Standard Test Method for Air Permeability of Building Materials (cfm/ft2 @1.57 psf)
- ASTM E1677
- Gurley Hill (TAPPI T-460) (sec/100cc)
Comparing House Wrap Vapor Permeability
Vapor permeability (measured in US perms) is the amount of vapor transmission that a house wrap permits over a time period. The ASTM E96 (Test Method for Water Vapor Transmission of Materials) measures perms. A high perm means the wrap has high vapor permeability. But, it can’t be so high that the moisture can penetrate from the outside into the wall system.
According to Joseph Lstiburek, with the Building Science Corporation, the ideal WRB perm, for balancing the inward and outward flow of moisture in a wall system, is between 10 and 20 perms.
Comparing House Wrap Drainage
Drainage is an effective method to lessen moisture infiltration to the wall assembly due to rain. A house wrap’s design should provide an integrated gap and a drainage plane so to resist bulk water.
Comparing 5 Common House Wrap Options
1. Barricade® Wrap Plus
Barricade® Wrap Plus is a non-perforated, non-woven polyolefin product with a semi-permeable membrane. Barricade® Wrap Plus’ breathable and micro-porous membrane controls air and moisture infiltration, yet its permeability allows evaporation of moisture vapor if it makes its way inside the wall assembly. Barricade® Wrap Plus resists rain (bulk water penetration).
- Barricade® Wrap Plus UV rating is 9 months; longer than some house wraps.
- Barricade® Wrap Plus is surfactant-resistant.
- Barricade® Wrap Plus is cold-resistant.
- Barricade® Wrap Plus has a tensile strength (ASTM D-5034) of 59 lbs/inch MD, 51 lbs/inch CD, which protects it against damage from wind, construction errors, etc.
- Barricade® Wrap Plus has 16 US Perms, ensuring an inward and outward balance of movement of moisture in a wall system.
- Barricade® Wrap Plus is a semi-transparent house wrap, which allows a view of the studs and sheathing surface and easier application than non-transparent wraps.
2. Tyvek® HomeWrap®
Tyvek® HomeWrap®, a product of DuPont™, is made from non-perforated, non-woven, high-density polyethylene fibers that are fused to create a uniform web. The web creates tiny pores that resist water and air penetration while permitting vapor to pass through.
Benefits of Tyvek® HomeWrap®
- Application of Tyvek® is over the open stud framing and sheathing, which saves on product costs.
- Tyvek® allows for weatherboard lap (external cladding) at window heads and other openings in a structure.
- Tyvek® comes in rolls which overlap at the seams to protect the structure from water intrusion.
Disadvantages of Tyvek® HomeWrap®
- Tyvek® HomeWrap® may be prone to damage due to high winds and moisture exposure because it only has a tensile strength of 30/30 lb/in.
- After only four months of exposure to UV rays, Tyvek® House Wrap may become damaged.
- Tyvek® HomeWrap® is not transparent, so it does not allow a clear view of the studs and sheathing surface during application, making the application more difficult than a semi-transparent house wrap.
- Tyvek® HomeWrap® is not surfactant resistant.
- Tyvek® HomeWrap® has a perm rating of 56 US Perms, much higher than the recommended perm rating.
3. HomeGuard® House Wrap
HomeGuard® House Wrap is an engineered, woven, polyolefin product designed for use as a secondary WRB.
Benefits of HomeGuard® House Wrap
- HomeGuard® House Wrap is permeable with a perm rating of 12 US Perms.
- HomeGuard® House Wrap is cold resistant.
- HomeGuard® House Wrap is a high-performing water-resistive barrier (ASTM D779),
Disadvantages of HomeGuard® House Wrap
- HomeGuard® House Wrap may be prone to damage due to high winds and moisture exposure because it only has a tensile strength of 52/30 lb/in.
- After only six months of exposure to UV rays, HomeGuard® House Wrap may become damaged.
- HomeGuard® House Wrap is not transparent, so it does not allow a clear view of the studs and sheathing surface during application, making the application more difficult than a semi-transparent house wrap.
4. CertainTeed CertaWrap™
CertaWrap™ Standard house wrap is a coated poly woven fabric weather-resistant barrier, manufactured by CertainTeed.
Benefits of CertaWrap™
- CertaWrap™ is surfactant resistant.
- CertaWrap™ is permeable with a perm rating of 11.7 US perms.
- CertaWrap™ has a tensile strength (ASTM D-5034) of 80 lbs MD, 87 lbs CD which protects it against damage during and after installation.
- CertaWrap™ passes the Gurley-Hill porosity test for air resistance.
- CertaWrap™ passes the ASTM D-779 for water resistance.
Disadvantages of CertaWrap™
- CertaWrap™ is not transparent, so does not allow a clear view of the studs and sheathing surface during application, making the application more difficult than a semi-transparent house wrap.
- After only six months of exposure to UV rays, CertaWrap™ house wrap may become damaged.
5. The ZIP System®
The ZIP System®, manufactured by Huber Engineered Woods, LLC includes ZIP System® sheathing panels and self-adhesive tape. The panels comprise oriented strand board (OSB) wood structural sheathing with a Grade-D 60-minute WRB exterior facer of medium density phenolic-impregnated polymer-modified product. The seam sealing tape is a polyolefin sheet, backed with acrylic adhesive.
Benefits of ZIP System®
- Installation of the ZIP System® is faster because the WRB and OSB are done in one step.
- The ZIP System® resists wind damage.
- The ZIP System® comes with a 30-year warranty, although it has some constraints.
Disadvantages of ZIP System®
- Improper taping between the panels creates a path for moisture to enter the walls.
- Dust, dirt, and low temperatures (below 20°F) reduce the bonding nature of ZIP System® tape, which voids the warranty.
- Installing the hardware over the WRB of the ZIP System® makes it more susceptible to corroding than framing hardware installed behind the WRB.
- The OSB structural panel of the ZIP System® is prone to absorbing moisture, which will damage the panels before installation.
- After only three months of exposure to UV rays, the ZIP System® may become damaged.
Make the Best Choice
A high-performing house wrap has the right balance of air and water resistance and vapor permeability to prevent air and moisture infiltration. It must also have the strength to withstand damage during and after construction.