Common Problems that Reduce the Effectiveness of Your House Wrap
High-quality house wrap is most often made of spun, high-density polyethylene fibers. It is a vapor-permeable material designed to simultaneously block the passage of liquid. Properly installed, it’s a WRB with the ability to resist moisture while allowing humidity to escape from exterior wall cavities, which is of particular importance in humid climates.
However, unforeseen problems with house wrap occur if it is improperly installed, exposed to the elements for too long or if it is damaged during installation. When siding or other forms of wall cladding are installed over damaged house wrap, the installation problems are concealed. The homeowner may experience drafts or moisture problems and be unable to find the source of the problem.
Some companies sell a proprietary tape that is to be used exclusively with their house wrap system, such as those sold for Typar house wrap. Proper application of tape is essential to create a continuous air barrier important for maximum energy savings. Because taping typically occurs only after the entire structure is wrapped, the conditions before taping are important.
Taping problems, however, can quickly compromise the house wrap’s effectiveness. Tape adhesion can be an issue, particularly if it is applied over a soiled or damp surface. There is another important consideration when taping a wrapped home – ambient temperature. Successful adhesion of the tape to a wrap is dependent on both moisture/humidity and temperature. Tape applied to house wrap that is too cold may not adhere properly. Wrinkling of the tape may also lead to unwanted air or water incursions.
Problems may also occur when an installer fails to use a tape roller during installation. Fastener placement is also critical to taping success. When house wraps fail and major structural damage occurs, contractors must often take corrective action at significant cost. In some instances, litigation is a possibility.
Too often, contractors are unaware of how quickly installed house wrap will deteriorate when left exposed to ultraviolet radiation for extended periods. Of course, UV radiation remains an issue even on cloudy days. In North America, the impact of UV radiation varies by season and by geographical location. That is, it is more of an issue in Phoenix than in Seattle.
The problem of excessive UV light exposure is significant because the water-resistant quality of the house wrap can degrade significantly. In particularly sunny locations, the water-resistant quality of the house wrap can deteriorate significantly in a few months.
When upper layers are not lapped over lower layers, moisture can get behind the house wrap. Also insufficient lapping can compromise water resistance. Horizontal joints that are lapped less than 6 inches, or vertical joints lapped less than 12 inches in areas of significant wind-driven rain are a potential issue.
House wrap installation around windows and doors requires knowledge and care to avoid subsequent moisture intrusion problems. A failure to cover the sill plate and foundation joint with house wrap can also compromise its effectiveness. When house wrap is improperly installed over wooden structures, seam leaks may occur, and they may remain undetected for years until structural damage occurs.
The DELTA®-VENT SA Solution
DELTA®-VENT SA is a WRB that addresses many of the problems common with other house wraps. It is a premium water-resistant air barrier that is aggressively self-adhering. DELTA®-VENT SA is a so-called “sticky wrap” that results in more airtight and watertight structures. Its self-adhering design eliminates mechanical fasteners, which further reduces the potential for leaks.
DELTA®-VENT SA is a more substantial WRB that resists damage during construction. The material is highly vapor permeable (50 perms), and its design promotes quick draining and drying. It is the only self-adhering and vapor-permeable WRB both evaluated by the Air Barrier Association of America and International Code Council (ESR 2932).
Cosella-Dörken delivers innovative, high-performance air and moisture barriers for commercial and residential construction sold under the DELTA® brand name. A North American manufacturer based out of Beamsville, Ontario, Cosella-Dörken Products, Inc. is a subsidiary of Ewald Dörken AG, a leading European developer and manufacturer of waterproofing and drainage products sold worldwide. Cosella-Dörken is known for delivering premium products while providing educational programs and full technical support. For more information, call 1-888-4DELTA4 (433-5824) or visit www.cosella-dorken.com.