The three common systems
| System | What it is | Things to know |
|---|---|---|
| EPDM | Synthetic rubber single-ply membrane | Long field record; averaged 17.7 years in one 20,000-roof survey[1] |
| TPO | Heat-welded thermoplastic single-ply | Newer; less long-term field data in the sources we found |
| Modified bitumen / built-up | Asphalt-based multi-layer sheets | Multi-ply asphalt averaged 13.6 years in the same survey, but 17.4 years in a 400-contractor survey[1] |
IIBEC's point is that the two biggest service-life studies disagreed, and that roofs built with upgraded components and details (the kind needed for longer manufacturer warranties) tend to last longer.[1] Ask for the specific system, thickness and warranty term in writing.
Buffalo-specific risks: ponding and snow
FEMA's snow load guidance flags water collecting where it should not on low-slope roofs as a warning sign of overstress, and notes that flat roofs with parapets, stepped roofs and roofs with equipment collect drifts unevenly.[2] Rain on snow and blocked drains add load.[2] With 95.4 inches of normal annual snow at the Buffalo airport,[3] keep drains and scuppers clear and ask how the design handles drifts against walls.
Wind also lifts low-slope membranes: Angi lists wrinkles, cracks and tears in rubber roofs as common wind damage.[4] Flat-roofed homes and garages in Buffalo, Kenmore, Tonawanda, Niagara Falls and lakeshore Lackawanna should get a check after big wind events.
Questions to ask a flat roof contractor
- Which membrane, what thickness, and is it fully adhered, mechanically fastened or ballasted?
- How will water reach the drains, and will you add tapered insulation to stop ponding?
- What is the manufacturer warranty term, and what is your workmanship warranty? (See our roof warranty guide.)
- Will the written contract list all of this? New York requires home improvement contracts to be in writing.[5]
Compare flat and commercial roofing contractors in your area.