Visible moisture is one thing, but the moisture you can't see can be just as problematic. “The below-grade stuff is even harder to figure out,” Horton says. “It comes from all directions.” That's why basement water-proofing and other below-grade considerations are so important, he adds.
Luckily, a number of manufacturers have developed products to help minimize the guesswork. Reynoldsburg, Ohio-based Tremco Barrier Solutions, for example, claims its Tuff-N-Dri waterproofing system keeps the foundation wall temperature closer to the air temperature of the basement, minimizing condensation and controlling moisture.
For the vulnerable areas under windows and doors, Wylie, Texas-based Carlisle Coatings & Waterproofing has introduced EZ-Pan, a sill pan flashing assembly comprised of a sill wedge, flashing, and pre-molded polyethylene corner pieces. The system reportedly provides a continuous water barrier and drainage plane—even in a sill's vulnerable corners.
Delta-Dry, a heavy-duty polyethylene membrane from Cosella-Dörken Products of Beamsville, Ontario, is another option. The system's dimple-and-groove design helps drain water and acts as a capillary break. It's also said to be impermeable to both air and moisture.
Products such as WeatherTex housewrap (above), Cedar Breather roofing underlayment, Delta-Dry polyethylene membrane (shown below), and plastic/rubber flashing panels make it easier for architects to keep moisture at bay. Using proper construction techniques and building for your region are still highly recommended.
Just this year, Reno, Nev.- based Fortifiber Building Systems Group introduced WeatherTex, a hybrid product that combines its Super JumboTex building paper and WeatherSmart nonwoven, nonperforated polymeric housewrap. The manufacturer says the weather-resistant barrier can be used in any climate and with any cladding.
Other new products include DuPont's Tyvek AtticWrap, a breathable membrane that helps reduce air leakage through the roof; Gorilla Wrap nonwoven, nonperforated housewrap from Denver-based Johns Manville; and an inventive line of plastic/rubber flashing panels for plumbing, electrical, gas, and HVAC exterior protrusions from Quickflash Weatherproofing Products in Las Vegas.
Even with all these options, there's no quick fix to be had and no substitute for sound construction practices. Wall assemblies and construction techniques should be chosen based on the climatic conditions of your area. While this may seem elementary, Lstiburek writes that it's not unusual to find “cold” climate building envelope designs used in “warm” climate regions.
Delta-Dry polyethylene membrane
“Building assemblies, in all climates, can get wet from the exterior by both liquid flow and capillary suction (rain, dew, and groundwater as moisture sources),” he explains. “Accordingly, techniques for the control of liquid flow and capillary suction are similar in all climates and are interchangeable.”
However, he warns, “building assemblies get wet by air movement and vapor diffusion in different manners depending on [the] climate and time of year. Therefore, techniques for the control of air movement and vapor diffusion are different for each climate and are seldom interchangeable between different geographical locations.”
Bottom line: There's nothing wrong with pushing the envelope in design, if you honor the local laws of Mother Nature.