A Flashing is a continuous piece of malleable sheet metal or other impervious material that is installed to direct water into safe surface areas and prevent it from entering the structure the building. It is placed around protrusions from the roof of a building (such as pipes and chimneys) or the edges of other roofs to deflect water away from seams or joints. Flashing may be exposed or concealed. Exposed flashing is usually of a sheet metal, such as aluminium, copper, painted galvanized steel, stainless steel, zinc alloy, lead or lead-coated copper:
- Apron flashing – a flashing with the lower edge lapped over the head of each tile
- Cover or counter flashing – a flashing which overlaps the sides of tiles
- Raked flashing – a flashing which covers an inclined intersection.
- Stepped flashing – a flashing used to cover an inclined intersection, secured into the horizontal joints
Wall flashing is typically found at interruptions in the wall, such as windows, doors and points of structural support to prevent water from entering the wall cavity or structure.