CSLB C-39 Roofing ContractorSteep-Slope RoofingEasy
A contractor is installing a new roof on a building where a chimney penetrates the roof slope. To ensure a watertight seal around the chimney, which type of flashing is specifically designed to be integrated with the shingle courses, allowing for movement between the roof and chimney?
- ACounter flashing
- BApron flashing
- CValley flashing
- DStep flashing
Show answer & explanationAnswer & explanation
Correct answer: D. Step flashing
Step flashing is used where a roof meets a vertical surface, such as a chimney or wall. Individual pieces are interwoven with each shingle course, ensuring a watertight seal while accommodating differential movement.
Why the other options are wrong
- A. Counter flashing (or cap flashing) is installed over step flashing and into the chimney mortar joints to protect the top edge of the step flashing.
- B. Apron flashing is typically a single piece used at the lower side of a chimney or skylight, not interwoven with shingles.
- C. Valley flashing is used where two roof planes intersect to form a valley, not around a chimney.
Step Flashing
Step flashing consists of individual, L-shaped pieces of metal flashing integrated with each shingle course where a roof slope meets a vertical wall or chimney.
- Interwoven with shingles for watertightness.
- Allows for thermal expansion and contraction between roof and vertical surface.
- Used on the sides of chimneys or walls.
Memory trick: Chimney's climb, step by time, with counter's prime.