Regardless of the material specified for use as your weather-resistant barrier (also known as WRB, building wrap or house wrap), proper installation is critical in order for the WRB to work as intended. Even if the barrier meets all code requirements, performance of the material can be compromised by a lack of attention to detail. The good news is, installing building wrap is simple if you stick to these four easy steps:
1. Step 1: 12” overlap and 1” overlap on the sill plate but for max protection 2-4”
Building wrap should be installed from the foundation upward, making sure to overlap joints with the higher course overlapping the lower. First, start at the bottom of one end of the wall with the printed side facing out. When starting at a corner, overlap by a minimum of 12”. Place the building wrap roll horizontally and roll out the first course evenly, covering rough window and door openings. A minimum of a 1" (25.4 mm) overlap on the sill plate is required; however, for maximum protection, a 2-4"(51-102 mm) overlap on the sill plate is recommended. Be sure to pull the building wrap snug and avoid wrinkles and creases.
2. Step 2: Use plastic-capped nails to attach the building wrap
Additionally, when installing a building wrap over metal frames, you’ll want to use screws and washers. Simply put, the use of caps seals holes made by the penetration of the fasteners. Studies show that homes where cap nails and cap staples were used to attach housewrap resisted air infiltration and water holdout better than those where caps weren’t used. If water is allowed to enter through the staple holes, it becomes trapped creating the perfect conditions for rot and mold. The more holes, the better the chance for complications and negative long-term effects on the building envelope.
3. Step 3: Overlap bottom layer by 6”, ensure proper shingling, cover all seams using tape
The upper layer of thebuilding wrap should overlap the bottom layer by a minimum of 6"(152 mm) vertically and horizontally. You should also take some time to ensure proper shingling throughout the installation to properly shed water. Once the structure is completely covered, tape all seams and penetrations. Sealing all laps and penetrations with the proper tape can improve the building wrap’s performance by 20 percent.
4. Step 4: Inspection forrips and tears
Once installation is complete, thoroughly inspect the building wrap for any tears before installing the cladding. Even the slightest tear can leave the wall at the mercy of Mother Nature.
Attention to detail when installing your WRB is the ounce of prevention that can help protect against damaging moisture, whether it originates inside or outside of the building. A weather barrier system that has been properly installed can help improve the durability of a building, indoor air quality and decrease potential maintenance costs by reducing the risk of moisture intrusion.