As the push to control moisture intrusion continues, it's important to remember that what's under the house is just as important as the house-wrap and the window flashing. Basements are prone to dampness, mustiness, and mold growth due to moisture intrusion, but can be protected—and made into comfortable living areas—with a variety of waterproofing solutions.
Foundation cracks, created as the concrete shrinks, cures, and settles, can allow water to easily infiltrate the structure, undermine the foundation, and spur the growth of mold. The biggest step in protecting below-grade spaces from moisture damage is to waterproof the foundation—walls and slab—during construction. Below-grade waterproofing has not received as much focus in the residential segment over the years as above-grade moisture intrusion remedies, but as the industry continues to study the entire building envelope for solutions to moisture woes, new technologies trickle down from commercial building, and builders look to prevent mold liability, below-grade waterproofing is gaining ground. “The waterproofing market continues to grow as a result of consumer demand for improved below-grade living space,” says Scott Young, senior North American residential market manager for Dow Building Materials, maker of the Styrofoam Perimate moisture-resistant exterior insulation, which installs over waterproofing membranes.
A variety of waterproofing barriers can be applied to the exterior of the foundation walls and under the slab, including spray-applied membranes such as Mar-Flex's QuickSeal and Tremco Barrier Solutions' Tuff-N-Dri Basement Waterproofing System; self-adhering membranes such as Grace Construction Products' FlorPrufe; and mechanical sheet systems that require fasteners such as Cosella-Dörken's Delta-MS or Armtec Ltd.'s System Platon.
According to manufacturers, an effective waterproofing barrier must not only prevent water from seeping through concrete, it must also be flexible to bridge the cracks that form over time. They also stress the differences between damp-proofing and waterproofing. “The terminology in the industry is used wrong. Many builders don't understand the difference,” says Brent Oakley, president of Mar-Flex. While damp-proofing products act as barriers to retard water penetration, they typically are not flexible enough to bridge settling cracks, and as they degrade they become brittle and eventually fail, he says.
Dealers who understand the benefits and differences of the various foundation waterproofing barriers on the market can use this knowledge not only to improve builder awareness of products but also, says Oakley, to expand installed sales offerings to include basement and foundation waterproofing. Some products are sold through traditional distribution channels, but others must be applied by manufacturer-trained installers. Some manufacturers, in particular those of spray-applied membranes, offer installer training that allows contractors and pro dealers to become qualified installers.
“What dealers should keep in mind is that as these markets grow, the market will unavoidably be flooded with different products, all at different prices,” says Larry Shapiro, worldwide director of marketing for Grace. “It takes a little bit of doing, but it's worth it to understand how these products are differentiated and to validate claims that manufacturers make.”