It’s easy for small amounts of water to enter a home’s wall cavity, both during and after construction. When water evaporates it becomes a gas (water vapor) that needs to escape. If the walls can’t completely dry, a home is more likely to experience mold and rot.
A building material’s ability to let water vapor pass through is called permeance, measured in units called “perms.” There are two ways that the American Society of Testing and Materials (ASTM) measures permeance in its E96 test: Procedure A (desiccant or “dry cup” method) and Procedure B (water cup or “wet cup” method).
Here are some common misconceptions about building enclosure performance and the truths behind them:
TRUTH: “Whether a vapor-control material is 5 perms or 35 perms, the drying rate is usually limited by other materials like the cladding,” says John Straube, a principal at RDH Building Science and an associate professor at the School of Architecture at the University of Waterloo in Canada.
TRUTH: “The house wrap industry emphasizes the ASTM E96 Procedure A or ‘dry cup’ test,” adds Straube. “But the test that’s more appropriate for in-service use of wood-framed buildings is really Procedure B or the ‘wet cup’ test. I have a colleague who says, ‘Procedure A measures how much water vapor passes through when there isn’t any water vapor, while Procedure B measures how much passes through when there is water vapor.’”
TRUTH: It defeats the purpose of an air/water barrier if a home’s exterior flashing isn’t done properly. “There are far greater mold risks when sheathing gets wet after the home is occupied than when it’s being built,” says Straube. “If windows leak into the wall, that’s really scary because you can’t see it.”
Learn more about the LP WeatherLogic™Air & Water Barrier system, the latest addition to LP’s portfolio of structural solutions.
While board and batten siding is typically made of wood, it can also be made from vinyl, fiber cement or even steel. But if you’re worried about durability and curb appeal—and these days who isn’t?—engineered wood siding is a smarter buy compared to traditional wood siding because it mimics its look but features greater durability and easier maintenance.Continue Reading
Flashing is a key part of the LP® SmartSide® Trim & Siding installation process, helping to protect homes from the elements by preventing moisture intrusion. When you are installing lap siding, incorrectly installed flashing may lead to moisture issues that can affect other aspects of the home, in addition to the siding.
When it comes to exterior cladding, homes require more than siding to protect them from the elements. Fascia and trim are two key elements that work together to create a protective barrier around the home, serving as a first line of defense along with siding.
In today’s landscape of high competition and new ways of interacting with clients, easy-to-access virtual resources have become even more important. That’s why LP® SmartSide® Trim & Siding is committed to providing you the tools you need to keep up with the changing landscape.