When housewrap was introduced in the late 1970s, its purpose was to prevent air and water from entering the stud wall cavity from the outside. But ongoing building science research has shown that moisture from the inside of the home may also contribute to a mold- and mildew-friendly environment in the wall cavity. As moisture concerns continue to rise, housewrap manufacturers are responding with new products that provide more aggressive moisture control.
“The biggest concern of homeowners and builders today is mold and mildew, so preventing moisture from entering the wall cavity, thus preventing an environment that mold and mildew can occur in, is very important,” points out Scott Gettelfinger, North American business manager for DuPont Building Innovations, maker of Tyvek Homewrap.
The average home produces up to 7 gallons of water each day from common human activities, says Pat Marcoullier, director of construction products for BBA Fiberweb, maker of Typar housewrap, water that generally escapes into the wall cavity. Today's housewraps, including Tyvek, Typar, Owens Corning PinkWrap, Dow Styrofoam WeatherMate, and others, not only keep out water and air from the home's exterior, but they also allow water from the interior to escape the wall cavity, manufacturers say. The material's ability to breathe—which varies depending on the product and its application—is one of the ways housewraps accomplish these goals.
The use of weather-resistive barriers is now required by the International Building Code (IBC) and has been adopted by many local code bodies. But builder knowledge of housewrap is still spotty. “There is a large percentage of builders who still don't understand the need for it,” says Marcoullier. Builders who have never used housewrap before may be caught off guard if and when their locales adopt the IBC's weather-resistive barrier requirement.
These builders will have to bring themselves up to speed on housewraps, their relative performance, and how to use them effectively, and dealers can be instrumental in that education. Mark Olson, national sales rep for the engineered films division of Raven Industries, maker of Rufco-Wrap, advises that dealers hold seminars to introduce contractors to the types of housewraps available, their different features, and installation techniques.
“Dealers need to know about installation methods so they can talk to their customers about how to install and use housewrap properly,” says Dan Partrich, marketing manager for Pactiv, maker of GreenGuard RainDrop housewrap.
“Now that drainage products have come out, builders have a better opportunity to reduce the potential for mold and mildew liabilities,” says Kurt Kronauge, national sales manager for Valéron Strength Films, maker of WeatherTrek with Valéron EVD housewrap.