CSLB C-39 Roofing ContractorFlashing, Ventilation and InsulationMedium
A technician installs step flashing along a shingle roof/sidewall intersection. Each individual step flashing piece must extend a minimum of how far up the wall and overlap the piece below it by how much?
- A2 inches up the wall, 1 inch overlap
- B6 inches up the wall, 3 inches overlap
- C8 inches up the wall, 4 inches overlap
- D4 inches up the wall, 2 inches overlap
Show answer & explanationAnswer & explanation
Correct answer: D. 4 inches up the wall, 2 inches overlap
Code requires each step flashing shingle to extend a minimum of 4 inches onto the wall surface and lap the piece below by at least 2 inches, ensuring continuous water shedding down the wall and onto the roof plane.
Why the other options are wrong
- A. Insufficient height and overlap for reliable water shedding.
- B. Exceeds code minimum; not the standard requirement.
- C. Far exceeds the required minimums.
Step Flashing Dimensions
Step flashing pieces must rise at least 4 inches up the sidewall and lap the previous piece by at least 2 inches to prevent water bypass.
- Installed with each course of shingles, not as one long strip.
- Minimum 4-inch wall leg per code.
- Minimum 2-inch overlap between successive pieces.
Memory trick: 'Four up, two over' keeps the water covered.