CSLB C-39 Roofing ContractorLow-Slope RoofingMedium
A sheet metal worker is installing counterflashing into a masonry parapet wall to cover the top edge of base flashing. To what minimum depth should the reglet (flashing receiver slot) typically be cut into the mortar joint for secure, weathertight anchorage?
- A2 inches
- B4 inches
- C1/4 inch
- D1 inch
Show answer & explanationAnswer & explanation
Correct answer: D. 1 inch
Standard sheet metal practice calls for cutting the reglet approximately 1 inch deep into the mortar joint so the counterflashing edge can be inserted, wedged, and sealed securely, preventing water infiltration behind the flashing.
Why the other options are wrong
- A. Deeper than necessary and may compromise the mortar joint's structural integrity.
- B. Excessive depth that risks damaging the masonry unit.
- C. Too shallow to hold the flashing edge securely or resist wind uplift.
Reglet Counterflashing Embedment
A reglet is a slot cut into masonry to receive and anchor the top edge of counterflashing, secured with lead wedges or fasteners and sealed with mastic.
- Typical minimum embedment depth is about 1 inch
- Reglet is sealed with sealant after flashing insertion
- Counterflashing overlaps base flashing to shed water
Memory trick: One inch deep keeps the flashing anchored and the water sealed.