Flashings are an important part of a building’s envelope system because they help prevent water from entering the structure at joints, transitions, openings, and other vulnerable areas. Common types of flashing include sheet metal flashing, through-wall flashing, and flexible flashing. Sheet metal flashing is typically fabricated from materials such as aluminum, galvanized steel, or stainless steel and is installed at areas such as wall penetrations, and openings to direct water away from the building.

Through-wall flashing is installed within exterior walls, usually at the base of walls, above openings, and at other locations where water may collect, allowing moisture to drain to the exterior. Flexible flashing is made from materials that can bend and conform to irregular surfaces and is commonly used around windows, doors, corners, and other transitions. Proper installation requires the flashing to be securely attached, correctly overlapped and sealed, and integrated with adjacent waterproofing materials so that water is continuously directed toward the exterior rather than into the building.