Renowned Independent 3rd Party Lab Concludes Brick Veneer is the driest of all wall panels evaluated
November 15, 2010 (Reston, VA) An independent 3rd party building products laboratory, a wholly owned subsidiary of the country’s pre-eminent trade association for the housing industry has recently completed a year-long field moisture study entitled “Moisture Performance Comparison of Typical Residential Wall Assemblies.” The project’s objective was to determine how exterior cladding can impact the moisture content of the wooden components in the wall construction, and the research was funded by the Brick Industry Association (BIA), the U.S. Department of Agriculture’s Forest Products Laboratory, and the U.S. Department of Housing and Urban Development. The results are in. Of the eight wall systems tested, which account for roughly 90% of the cladding systems used today, brick veneer wall assemblies performed the best overall in controlling moisture.
This study was initiated due to moisture issues having become an increasing concern in residential construction. While builders address growing demands for occupant comfort and energy-efficiency, modern construction practices have resulted in tight walls that are highly insulated and sealed against air filtration. When moisture is not sufficiently controlled with these lighter, tighter building methods, the risk of mold growth, wood rot and infestation by insects, reduced efficiency of insulation and corrosion of fasteners embedded in wood all increase dramatically. The report attributes the lower moisture content in the wood components to brick’s inherent thermal mass properties, the one-inch air space in the brick veneer wall and the increased thermal absorptance of the test brick’s red color.
“The lab report’s findings are extremely significant,” notes J. Gregg Borchelt, President & CEO of BIA. “Builders will want to choose brick if they wish to provide their customers the protection of a superior wall system – instead of one that is just ‘good enough.’”
The field study was designed to collect moisture performance values at regular intervals from key components within a pair of wall assemblies constructed with each of eight different cladding types. Each wall assembly consisted of interior gypsum board, wood studs with fiberglass insulation between the studs, sheathed with either OSB or plywood and clad with brick veneer, vinyl siding, fiber cement, manufactured stone or stucco. Each wall assembly was then subjected to ambient weather conditions over a one-year period. In addition, a portion of water resistant barrier was compromised and the wall assembly behind it subjected to a daily water injection over a five-day period to evaluate its ability to dry after a leak. The data recorded for each wall assembly included wood stud moisture content, wood-based sheathing moisture content, stud bay relative humidity and stud bay temperature. While all assemblies performed adequately under normal conditions, brick performed significantly better overall.
“We all know that builders depended on brick’s thermal mass properties for centuries in structural building. Interestingly, these very same properties have proven to be enormously beneficial in contemporary, veneer wall construction.” Borchelt adds. To download a complete copy of this report, go to www.gobrick.com/nahbrcreport.
About the Brick Industry Association:
The Brick Industry Association (BIA) is the national trade association representing distributors and manufacturers of clay brick and suppliers of related products and services. BIA’s primary mission is to increase the market share of clay brick and safeguard the industry. Since its founding in 1934, the association has been the nationally recognized authority on clay brick construction and represents the industry in all model building code forums and national standards committees. BIA is involved in a broad range of activities that appeal to architects, builders, community officials, and consumers, including Technical Notes on Brick Construction, Brick in Architecture, Brick In Home Building, Builder Notes, national awards competitions, educational seminars, and numerous other programs. BIA also advocates the industry at the federal, state, and local level with its environmental, health, and safety work as well as educational programs for local municipal and planning officials. Along with the national headquarters, BIA is comprised of regions that manage programs in the Heartland, Midwest/Northeast, Southeast, and Southwest. For more information, go to www.gobrick.com or www.greenbrick.com.