High Quality Content by WIKIPEDIA articles! A rainscreen is the exterior weather-facing surface of an exterior wall detail that stands off from the moisture-resistant surface of the structural backup wall. The rainscreen is the first interruption between conditions that exist on the outside of a walled building and conditions that are required on the inside of a walled building. A veneer that does not stand off from the moisture-resistant surface of the structural backup wall to create a cavity is not a true rainscreen. However, a masonry veneer can be a rainscreen.