CSLB C-39 Roofing ContractorSteep-Slope RoofingHard
A roofer is installing step flashing where a sloped composition shingle roof meets a vertical sidewall. What is the minimum required vertical leg height of each step flashing piece up the sidewall?
- A6 inches
- B2 inches
- C4 inches
- D8 inches
Show answer & explanationAnswer & explanation
Correct answer: C. 4 inches
Step flashing pieces must extend a minimum of 4 inches up the vertical sidewall and typically 4 inches onto the roof deck, with each piece overlapping the one below by at least 2 inches, ensuring water is directed away from the wall-roof intersection.
Why the other options are wrong
- A. 6 inches exceeds the minimum but is not the standard requirement.
- B. 2 inches is insufficient vertical coverage and risks water infiltration behind the wall.
- D. 8 inches is excessive and not a typical code minimum.
Step Flashing Dimensions
Individual L-shaped flashing pieces installed at each shingle course where a roof meets a vertical wall.
- Minimum 4in up the wall, 4in onto the deck
- Each piece overlaps the one below by 2in minimum
- Must be covered by siding, never left exposed
Memory trick: Four up, four over, keeps water in the clover.