Flat roofs are a different trade
Flat and low-slope roofs live by different rules than pitched ones: they hold water instead of shedding it, so seams, penetrations, and drainage decide everything. King County has a lot of them, mid-century ramblers and additions, modern infill with low-slope sections, and commercial flatwork up and down the valley.
What fails on a flat roof?
- Seams and laps, the joints are the weak points on every membrane system
- Ponding water, standing water past a day or two accelerates every failure mode
- Penetrations, vents, skylights, drains, and HVAC curbs; most flat-roof leaks trace to a penetration
- Drains and scuppers, clogged drainage turns a workable roof into a shallow pool in the wet months
Repair or recover?
An isolated seam or penetration failure on a sound membrane is a real repair. A membrane that's brittle, splitting across the field, or holding widespread ponding is telling you the system is done. Torch-down and TPO repairs differ enough that the quote should name the existing system and the repair material, not just say "patch it."
What should a quote include?
Identification of the current system (torch-down, TPO, modified bitumen, EPDM), the repair or recover scope, how drainage and ponding get addressed rather than ignored, insulation condition where it's open, and warranty on the repair itself. Flat roof work is skilled work; a shingle crew guessing at a torch-down seam is how small leaks become big ones.
