The first question you might be asking is: what is a housewrap? Housewrap is a synthetic material used to cover the exterior of a house before the final exterior wall finish is applied. Some of the common product names that you may have seen are Tyvek®, WEATHERMATETM and GreenGuard. But why use a housewrap? What does it do?
Housewraps perform 4 primary functions:
· Keeping water out: No matter how well the final exterior wall finish has been applied, water may still penetrate. For example the caulking may fail between a window and the brick, a crack may form in a mortar joint in the stone or brick veneer, the wind may drive rain in the joints of vinyl siding. Whatever the reason, water may get behind the exterior veneer. This is where a housewrap comes into play. It covers the wall directly behind these veneers preventing water from penetrating and entering the wall cavity possibly causing water or mold problems on the framing, drywall or insulation.
· Letting water vapor escape: A well-engineered housewrap also allows vapor that is in the wall system escape rather than trapping the vapor in the walls. This may sound counterintuitive, but moisture (vapor) is constantly moving through the walls of our homes. When warm moist air inside the house is moving towards the outside, the housewrap should allow the vapor through and not trap the moisture in the wall.
· Controlling air flow: Controlling air movement through the walls of a house is just as important as good insulation. A house that leaks a lot of air either by allowing air into the house (infiltration) or allowing air out of the house (exfiltration) will be more expensive to both heat and cool. A well installed housewrap reduces the air movement both in and out of the house; thereby helping lower heating and cooling costs and keeping the house move comfortable.
· Perform as intended: A good housewrap needs to be built tough and withstand the elements during construction. A product that tears easily or that cannot be repaired during construction will not perform its primary functions listed above.
If you have questions about why we use the products that we do on your home, please ask us. We love to talk about the science behind our building.
At Brennan Homes, we strive to always be accessible to our customers – whether you’re a homeowner or just curious about building one of our custom homes.