Field & trade terms
Flashing
Flashing is the sheet metal or membrane installed at the vulnerable seams of a building to catch water and shed it back to the outside. Think roof to wall, window to opening, deck to cladding. It works entirely by lapping: upper layers over lower, so gravity keeps water on the surface and out of the wall. Reversed laps or missing pieces don't leak on install day; they leak two winters later, which is why flashing is inspected before it's covered.
Run it with the Photo Gate
Waterproofing inspection checklist
12 items · 26 photos required
How it shows up on site
You see flashing at head, sill and jamb of window and door openings, at roof-to-wall transitions and penetrations, at deck ledgers and at the base of cladding. The whole game is shingle-style layering, with each piece integrated into the water-resistive barrier so the drainage plane is continuous.
What an inspector looks at
The check is direction and continuity: does water hit each flashing and get thrown out rather than led in, are the laps correct, is the sill pan turned up at the back and ends, and is everything tied into the barrier rather than caulked over it. Sealant is a backup, never the flashing.
Because RTI closes items on a photo, flashing is documented while it's still exposed: sill pans, head flashing and roof transitions are shot before siding, trim or roofing hide the laps for good.
Guides that use it
- How to inspect a roofWalk a roof the way it goes together (deck, dry-in, flashing, penetrations, edge metal) and catch the leaks at the details before they're covered.
- How to inspect masonryInspect masonry as it rises (units, mortar, reinforcement, grout, and flashing), because a bearing wall or veneer is covered course by course.
- How to inspect the building envelopeInspect the envelope as a system (air barrier, water-resistive barrier, flashing, transitions, and sealants) with the continuity and mock-up that make it perform.
- How to inspect windows and glazingInspect windows and glazing from rough opening to seal (pan flashing, anchoring, integration with the WRB, and glazing), where water and air most often get in.
Checklists that put flashing to work
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related terms
- Weep holeA small opening left at the base of a cavity wall or window so water that gets behind the face has a path back out.
- Dry-inThe point at which a building is closed to weather: roof, wall barrier and openings sealed enough to keep water out and let interior work start.
- Vapor barrierA sheet material that limits how much water vapor diffuses through an assembly, placed to keep condensation from forming inside the wall or floor.
- PenetrationAny point where a pipe, conduit, duct or cable passes through a wall, floor or roof, leaving a hole that has to be sealed back to match the assembly it crosses.
- Air barrierA continuous plane of materials that stops air from leaking through the building enclosure, sealed at every joint, seam and penetration.
- UnderlaymentThe layer between structure and finish (under roofing, flooring or tile) that adds water resistance, a smooth base or the right bond surface.
Knowing the term is step one. Proving it is the job.
RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.
30-day trial · No card required