Flashing is a relatively small roofing component, yet it’s a crucial part of every type of roofing system that can help prevent major roof damage. In this blog, the local roofing contractors at Mass-Tech Roofing and Building Co. share a quick guide on flashing.
What Is Roof Flashing?
Every roof has breaks in the roofing material such as seams and transitions between roofing planes, which are vulnerable to water infiltration. Flashing protects these areas from leaks. Some types of flashing help route rainwater to the gutter troughs. A typical commercial or residential roof may utilize one or more of the following types of flashing:
- Valley Flashing — If you have a sloped roof, it probably has flashing on its valleys. Valley flashing is made from strips of metal with a profile shaped like an inverted letter “T.” The vertical “fin” functions as a barrier that prevents rainwater from flowing from one plane into another’s gap.
- Continuous and Step Flashing — This type of flashing is installed where a roofing plane meets a wall, dormer or chimney stack. The “continuous” part of the flashing follows the side facing the roof edge, and is usually made of a single piece. The “step” part is installed on the side that faces the roofing slope, with steps that follow the roofing shingles. The ridge-facing part may also have a triangular piece called a “cricket” that helps divert rainwater to the sides.
- Drip Edge — The drip edge is a long strip of flashing that’s installed at the first row of shingles. It features a profile shaped like an inverted letter “L” that prevents rainwater from infiltrating the roof edge. Most new roof installations feature this component, but it can also be added to existing roofs.
- Rubber Boots — Also known as vent pipe flashing, rubber boots protect the base of vent pipes and protrusions of similar size. They look like road cones prior to installation. The ends are trimmed to match the pipe circumference.
How Does Flashing Prevent Roof Damage?
The perfect roof would be seamless as an egg, with no points for water to infiltrate. However, this is not possible because of breaks in the roofing plane, as well as the need for vent and chimney pipes. Without flashing, rainwater would easily infiltrate these areas. It should be noted that flashing may get dislodged, damaged or corroded and will need to be replaced. It is normal for any roof to undergo flashing replacement at least once in its lifetime.