Flashing, Terminations, and Penetration Details
Flashing, Terminations, and Penetration Details
This domain tests the details that stop water at edges, walls, curbs, drains, and penetrations. The exam focuses on flashing height, counterflashing, termination bars, and reinforcement-not on generic sealant calls.
Core rules
- Base flashing should extend above the finished roof surface as required by code and manufacturer; a common minimum is 8 in (200 mm), and higher at parapets or where snow, drainage, or code demands.
- Counterflashing must overlap the base flashing and be secured in a reglet or wall. Do not rely on sealant alone as the primary termination.
- Use termination bars with fasteners at membrane edges, then seal the bar and edge per specification. Provide a drip edge at exposed edges.
- At penetrations, use the approved boot, curb, or pitch pan. Reinforce corners and pipe penetrations with additional plies; maintain lap direction.
- At drains and scuppers, install clamping rings and flashing per manufacturer. Expansion joints need a designed assembly, not a folded membrane.
Worked example
A pipe penetrates a roof with no curb and the installer proposes a sealant collar. That is not an acceptable primary detail for a membrane roof. Build an approved pitch pan or boot with a reinforced base flange, extend the flashing above the water line, and counterflash or clamp as required. The reason is movement and thermal cycling will break a sealant-only collar.
Traps
Short flashing; sealant-only terminations; missing counterflashing; incompatible sealant; no reinforcement at corners; flashing buried below roof surface.