CSLB C-39 Roofing ContractorSteep-Slope RoofingHard
A contractor is installing a new roof on a building where a skylight penetrates the roof plane. Which type of flashing system is most critical to ensure a watertight seal around the entire perimeter of the skylight?
- ACurb flashing
- BHead flashing
- CStep flashing
- DApron flashing
Show answer & explanationAnswer & explanation
Correct answer: A. Curb flashing
While apron, head, and step flashings are all components of a skylight flashing system, 'curb flashing' refers to the integrated system that surrounds the entire perimeter of the skylight curb, ensuring a continuous watertight seal where the skylight meets the roof deck. Often, this is a pre-manufactured system specifically designed for the skylight.
Why the other options are wrong
- B. Head flashing is used at the top edge of a skylight to divert water around and away from the top.
- C. Step flashing is used along the sides of a skylight to interleave with shingle courses, but a comprehensive 'curb flashing' system encompasses the entire perimeter.
- D. Apron flashing is typically used at the bottom edge of a skylight to divert water over the shingles below.
Skylight Flashing System
A comprehensive system of metal components designed to prevent water intrusion around roof penetrations like skylights.
- Multiple components work together.
- Critical for watertightness.
- Often pre-manufactured as a kit.
Memory trick: Around the curb, the flashing does its work, keeping leaks at bay, no lurk.