This guide advances the goal of designing, building, and maintaining houses that manage moisture effectively. As with any goal, moisture-resistant housing requires decisions – decisions by designers, decisions by builders, decisions by remodelers, decisions by trades, and decisions by homeowners. Therefore, this guide is a resource for good decision making in applying moisture management best practices.
By making moisture-resistant best practices available in an easy-to-use form, a variety of the most common moisture-related problems in homes can be avoided. These problems include rain penetration, structural decay, mold growth, high indoor humidity, condensation, wet foundations, ice dams, and many others that are well known to builders, homeowners, and insurers. For the most part, these problems are preventable or controllable, but only if timely decisions are made and acted upon. While Benjamin Franklin’s advice that "an ounce of prevention
is worth a pound of cure" was originally focused on preventing fires, it applies equally well to preventing moisture problems in homes.
Drawing from practical experience and the best available technical resources, this guide assembles proven, state-of-the-art moisture management best practices. These practices address topics directly related to moisture control – like window flashing – as well as less obvious issues that still influence the behavior of water in a house, like the moisture implications of duct leakage. The application of these practices will provide a home with multiple lines of defense against moisture, so that as a home ages or certain details begin to fail, the overall structure will still manage moisture effectively. Also, many of the best practices featured in this guide are tailored for important site-specific factors, such as climate or decay hazards that may vary widely around the U.S.
Finally, good moisture management involves a degree of uncertainty in regard to judgment as well as scientific knowledge. And because the best practices in this guide are faced with this challenge, they should not be construed as absolutes. Equally effective or better alternatives are
possible and encouraged. This guide is meant to promote forward thinking - not stifle it with "one-size-fits-all" solutions. And most importantly - if you are specifically trying to address or prevent moisture problems, you have already made the most important "best practice" decision.
U.S. Department of Housing and Urban Development
Office of Policy Development and Research
Newport Partners LLC