The purpose of this guide is to help the builder understand what causes moisture problems in buildings, how to repair them, and how to avoid them. The guide is divided into two parts. The first discusses the three main approaches to solving moisture problems: Controlling Moisture Sources, the Ai r-Barrier System and the Rain-Screen Principle. The second part is divided into six sections, each dealing with a particular area of the building: attics, wall cavities, basements and crawl space, exterior siding, interior surfaces, and windows. Each of the six sections identifies some common moisture problems, explains their probable causes and suggests possible solutions.