NAHB Research Center
A successful method for deterring rainwater intrusion into walls is the rain screen approach. You have probably seen them before-even a rain fly over a tent is a simple example of rain screen. Rain screens shed most of the rain and manage the rest, preventing moisture intrusion and the resulting premature decay in homes. Rather than attacking the symptoms of moisture intrusion, rain screens tackle the source-the forces that drive water into the building shell. By neutralizing these forces, rain screens can withstand extreme environments. They appear to be effective in any climate and handle any weather condition short of a disaster.