Bricks outperform against moisture, study says
A recent study by the National Association of Home Builders Research Center compared moisture resistance among typical residential exteriors and found brick veneer provided the highest in moisture resistance and dryness.
The study aimed to determine how exterior cladding impacts the moisture content of the wooden components in wall construction. The study showed that brick veneer outperformed the other wall systems tested, including vinyl, fiber cement, manufactured stone and stucco siding, which account for approximately 90% of the cladding systems used today.
"The lab report’s findings on brick’s superior moisture resistance are extremely significant,” noted J. Gregg Borchelt, president and CEO of the Brick Industry Association, which funded the study along with the U.S. Department of Agriculture’s Forest Products Laboratory and the U.S. Department of Housing and Urban Development. “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.’ ”
According to the BIA, modern construction practices to increase comfort and energy efficiency have resulted in tight walls that are highly insulated and sealed against air filtration. When moisture is not sufficiently controlled, risks increase dramatically for mold growth, wood rot and infestation by insects, reduced efficiency of insulation and corrosion of fasteners. The report attributes the lower moisture content in the wood components to brick’s inherent thermal mass properties, the 1-in. air space in the brick veneer wall and the increased thermal absorption of the test brick’s red color.
Each wall assembly test 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 and was then subjected to ambient weather conditions over a one-year period. Additionally 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 full report can be viewed at gobrick.com/nahbrcreport.