Breaking Old Rules for Air-Barrier Installation
Green Building Attributes
There are several factors that make a self-adhered, water-resistive, vapor-permeable air-barrier sheet membrane beneficial to an architect’s sustainable building goals. If one is trying to meet the criteria of the Living Building Challenge, look for a membrane that is void of all indicated red-list chemicals.
A membrane might be desired that is highly UV resistant, which means it can remain fully exposed for up to 180 days prior to installation of cladding system. With an open-joint cladding system, the membrane must be UV resistant.
Also, self-adhered, water-resistive, vapor-permeable air-barrier sheet membrane protects against water intrusion, but allows building materials that may have become wet during the construction phase to dry out, reducing the risk of wood rot, deterioration, or corrosion.
In the USGBC’s LEED green building certification program, a self-adhered WRB/air-barrier membrane can contribute to credits that address low-emitting materials such as adhesives and sealants.
At the National Renewable Energy Lab in Golden, Colorado, the only national laboratory solely dedicated to advancing renewable energy and energy-efficiency technology, a self-adhered, water-resistive, vapor-permeable air-barrier sheet membrane was chosen to protect the building envelope. The lab achieved LEED Platinum status.
Photo courtesy of VaproShield
The self-adhered, vapor-permeable air-barrier membrane contributed the building’s overall energy efficiency by being part of the continuous air-barrier system.
Conclusion
There is an art and science to designing and constructing buildings that are beautiful, comfortable, healthy, resource efficient, and durable. An effective building envelope is critical to a building that will last and reduce the architect’s risk. The weather-resistive air barrier should stop air and resist water. In addition, the installation should be compatible with today’s level of skilled labor, or lack of it, and embody qualities that allow it to be installed in freezing weather and without deployment of extensive equipment and void of pollutants. When determining the right WRB/air barrier for the building, the architect should consult with experts and be sure to ask all the right questions. If one is designing a beautiful and/or functional building, specifying a superior building envelope could give that building added longevity, and increase the architect’s reputation and standing.
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