CSLB C-39 Roofing ContractorFlashing, Ventilation and InsulationMedium
A roofer is flashing a skylight installed on a composition shingle roof. Which flashing component is installed last, at the top (upslope) edge of the skylight curb, overlapping the roofing material above it?
- AHead flashing
- BStep flashing
- CCounter flashing
- DApron (bottom) flashing
Show answer & explanationAnswer & explanation
Correct answer: A. Head flashing
Skylight flashing follows a shingle-style, water-shedding sequence: apron flashing goes in first at the bottom, then step flashing up the sides, and finally head flashing is installed at the top, tucked under the upslope shingles so water sheds over it away from the curb.
Why the other options are wrong
- B. Step flashing is interwoven along the sides, installed before the head flashing.
- C. Counter flashing is typically used with masonry, not the top of a skylight curb.
- D. Apron flashing is installed first at the bottom of the curb, not last at the top.
Skylight Flashing Sequence
Skylight flashing is installed shingle-fashion: apron (bottom) first, step flashing up the sides, and head flashing last at the top under upslope shingles.
- Apron flashing = bottom, installed first
- Step flashing = sides, interwoven with shingles
- Head flashing = top, installed last, under upslope shingles
Memory trick: Bottom to top, like shingles: apron, step, then head on top.