In construction and roofing, flashing refers to a thin, usually metal material that is installed to prevent water from penetrating a building or roof. Flashing is typically installed in areas where there is a change in plane or material, or where a joint or seam is present, such as around chimneys, roof vents, skylights, and at the junction of roof planes or walls.
The purpose of flashing is to direct water away from vulnerable areas and to prevent it from penetrating the building envelope, which can lead to water damage, rot, and mold growth. Flashing is usually made of metals such as aluminum, copper, or galvanized steel, and is designed to be durable and long-lasting.
Flashing can take many different forms, depending on the location and purpose. Some common types of flashing include step flashing, which is used to protect the intersection of a roof and a vertical wall; valley flashing, which is used to protect the intersection of two roof planes; and drip edge flashing, which is used to protect the edges of a roof and direct water into gutters.
Proper installation of flashing is essential to its effectiveness. Flashing should be installed in accordance with local building codes and manufacturer’s specifications, and should be integrated into the roofing or wall system in a way that ensures a continuous, water-tight seal.
Overall, flashing is a critical component of a well-designed and well-constructed building or roof system, and is essential to preventing water damage and preserving the structural integrity of the building.