Flashing & Detailing: the full procedure

Install and integrate flashing at every transition and penetration so water is directed off the roof rather than into the structure.

• Applies to: Crew Lead / Senior Roofer
• Frequency: Per job with penetrations or transitions
• Scope: Covers flashing of valleys, walls, chimneys, and penetrations. Any soldering/hot work, masonry cutting, or structural attachment DEFERS to code, a licensed roofer, and the safety plan; all height work follows OSHA fall-protection standards.

What you need

• Step/counter/apron flashing
• Pipe boots
• Valley metal
• Sealant/roofing cement
• Snips
• Hand seamer

The procedure, step by step

1. Plan the water path — Identify every wall, valley, chimney, and penetration and confirm how water sheds across each before installing metal.
2. Set valley flashing first — Install valley metal or membrane per the chosen open/closed method so it underlies adjoining courses.
3. Step-flash walls course by course — Interleave step flashing with each shingle course at sidewalls; never substitute a continuous bead of cement for stepped metal.
4. Flash chimneys with apron, step, and counter — Install apron at the front, step up the sides, and counter/cricket at the back; masonry reglet cutting defers to code and a licensed trade.
5. Seat pipe and vent boots — Slide boots under upslope courses and over downslope courses so the shingle laps shed onto the flange.
6. Integrate counter-flashing — Lap counter-flashing over base/step flashing so no fastener or seam faces uphill water.
7. Seal only as a supplement — Use sealant where the manufacturer specifies, never as the primary water barrier.
8. Inspect each detail — Verify every flashing laps correctly and no reverse laps or exposed fasteners remain.

Quality check before you finish

• Every penetration and transition flashed (not just caulked)
• Step flashing interwoven course-by-course at walls
• Chimney apron/step/counter all present and lapped correctly
• Pipe boots lapped under-upslope / over-downslope
• No reverse laps or uphill-facing seams
• Sealant used only as a supplement per spec
• Hot work / masonry cutting deferred to qualified trade and code

This is a free, source-anchored standard operating procedure (SOP) you can print and hand to staff. It documents the work sequence for a Roofing business — not safety or regulatory rulings, which defer to the cited authorities, the applicable code, and your own health-and-safety plan. Open the tool above to print it, toggle ink-saver, or (with a free ToolFluency Business account) edit it to match your own workflow.

Sources

• NRCA (nrca.net)
• ARMA (asphaltroofing.org)
• OSHA (osha.gov)