While flashing is available in a number of different materials the most commonly used is galvanized metal. Flashing is used for protection against leaks in vulnerable areas of the roof and/or where there is heavy water runoff. One way to think of flashing is like a kind of metal molding around chimneys, dormers, vents, skylights, and in valleys those areas where leaks are most likely.
The most common types of flashing are:
Vent pipe flashing – used to protect the area around a vent it typically has a flange at the bottom which is incorporated into the shingles as they are installed.
Valley flashing – protects the valleys of a roof. Flashing is installed on top of the felt paper and then the roofing material is installed over top.
Z flashing – used for flashing the area where a roof or deck meets a wall.
Step flashing – creates a step like appearance on the side of a chimney or dormer. This is created by individual strips of flashing being added with each layer of shingles.
Lead flashing – used with tile roofs the lead is formed to the shape of the tile.