What this covers
A flat roof is really a low-slope roof, and it depends on a continuous membrane, insulation that slopes to the drains, and flashing at every parapet, curb and pipe. The roofer removes or evaluates the old roof, repairs the deck, lays tapered insulation and a cover board, installs the membrane, whether TPO, EPDM, PVC or modified bitumen, and terminates it at parapet walls with metal coping and at the edges with drip edge or gravel stop. Drains and scuppers are flashed and kept clear. Careful work shows in positive drainage with no ponding, properly welded or adhered seams, and flashing that goes up and over, not just against, every wall.
When to call
- Water standing on the roof two days after rain.
- Blisters, open seams or cracked flashing at the parapet.
- Stains on a ceiling under a flat section of the house, porch or garage.
- A flat roof past its expected life being evaluated for replacement.
What to expect
- SurveyThe roofer maps ponding, checks seams and flashing, and probes for wet insulation.
- Choose a systemMembrane, insulation and drainage improvements are proposed for the building and climate.
- InstallOld roofing comes off, the deck is repaired, insulation is tapered to the drains and the membrane installed.
- Flash and finishParapets, curbs, pipes and drains are flashed, coping set, and you review the roof.
Get a certified company
Look up a certified company by ZIP code. Every company's license, insurance and trades are verified before it is listed, and placement is never paid.
Questions people ask
Which membrane is best?
Each has strengths: TPO and PVC are heat-welded and reflective, EPDM is simple and long-proven, modified bitumen is tough underfoot. The installer's skill with the chosen system matters more than the material.
Why does ponding matter?
Standing water stresses seams, grows algae and finds any pinhole. Tapered insulation and clear drains keep the roof dry between rains.
How often should a flat roof be looked at?
Twice a year and after major storms, clearing drains and checking seams and flashing. Small repairs caught early are the whole game on a flat roof.
Related: TPO roofing · EPDM rubber roofing · Modified bitumen roofing · All roofing and gutters
This page describes what the service involves. The company you hire sets the scope, the schedule and the price, and your contract is with that company. We verify credentials and collect reviews from real jobs. We do not guarantee any company's workmanship. Safety steps are general guidance. When in doubt, leave the home and call 911.