Trade walkthroughs
How to inspect a roof
Roofs almost never fail in the field of the membrane. They fail at the transitions: the penetrations, the terminations, the tie-ins where two planes or two materials meet. The only way to catch those is to inspect the roof in the order it's built, photographing each layer while the one under it is still visible.
For the roofing foreman checking their own crew, or the GC's superintendent verifying a roof before it's accepted and closed in.
Step by step
Confirm the deck is sound, dry, and fastened
Before anything goes down, walk the deck for fastening pattern, deflection, and moisture. On a nailable deck check for gaps and protruding fasteners; on steel or concrete confirm the substrate is clean and dry. A wet or springy deck is a defect you can't fix after the membrane is on.
Verify underlayment and the dry-in
Check that underlayment laps run shingle-fashion, laps meet the manufacturer's minimum, and fasteners or adhesive match the spec. This is the dry-in — the point the building is weathertight — so photograph coverage and laps before any covering hides them.
Inspect every penetration and its flashing
Pipes, curbs, vents, and equipment supports are where roofs leak first. Confirm each penetration has the right flashing, boot, or pitch pocket, that it's sealed and mechanically fastened, and that the membrane turns up and terminates correctly.
Check base and counterflashing at walls and curbs
At every vertical — parapets, walls, curbs — verify base flashing height, that counterflashing laps over it, and that terminations are fastened and sealed. Reglets and termination bars should be continuous, not skipped at corners.
Confirm the field membrane and its seams
Walk the field for seam width, welds or adhesive bond, fastener rows, and any fishmouths, wrinkles, or bridging. On single-ply, probe or check welds per the manufacturer's method; on built-up or mod-bit look for full embedment and no voids.
Verify drainage and slope to the drains
Flood-test or observe that water runs to drains and scuppers with no ponding beyond what the spec allows. Confirm drains are clamped, strainers are on, and crickets and tapered insulation actually move water where the drawings say.
Inspect edge metal, coping, and terminations
Edge metal and coping take the wind uplift, so check cleat engagement, fastener spacing, joint covers, and sealant at laps. Loose or under-fastened edge metal is a blow-off waiting for the first storm.
Document the assembly and close the inspection
Photograph each completed area against the checklist so the covered layers are provable later. Record any deficiency as a nonconformance and hold the area until it's corrected — don't accept the roof around an open defect.
What gets missed
- Accepting the field of the roof while corners, curbs, and penetration flashings go unphotographed.
- Signing off a dry-in after underlayment laps and fastening are already covered by insulation or membrane.
- Missing ponding water because the roof was walked dry instead of during or after a flood or rain test.
- Letting edge metal and coping fastening slide — the exact detail that fails under uplift.
- Treating the manufacturer's warranty inspection as the same thing as your own quality check; it isn't.
Questions people ask
- When should the roof be inspected — during or after installation?
- Both. The deck, underlayment, and flashings have to be checked as they go on, because they get covered. The field membrane, drainage, and edge metal are checked as they complete and again at final.
- Does my inspection replace the manufacturer's warranty inspection?
- No. The manufacturer's rep inspects for warranty compliance and issues the warranty; your walk verifies the work against the drawings and specs. Run both — they catch different things.
Standards behind it
Terms worth knowing
Checklists that make this a one-tap job
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related guides
- 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 insulation before coverInspect insulation and its air and vapor barriers before drywall covers them — coverage, fit, continuity, and the gaps that become thermal and moisture problems.
- How to document inspections with photosMake inspection photos that actually prove something: shoot the concealed condition before cover, tag location and date, and tie each shot to the checklist item it backs.
Reading the steps is one thing. Proving you walked them 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.