Flashings are integrated with drainage planes creating, for all practical purposes, a flashing for the entire assembly. Flashings are the most under-rated building enclosure component and arguably the most important. The most elegant expression of this concept is a flashing (see Roof to Wall Flashing with Foam Sheathing). Sooner, may not always be practical-such as at window openings where draining a window into a drainage space behind a cladding is often more practical than draining them to the exterior face of the cladding. In general, the sooner water is directed out the better.
The “down” direction harnesses the force of gravity and the “out” direction gets the water away from the building enclosure assemblies, openings, components and materials. Gravity is the driving force behind drainage.
