Flat Roof · 2026 Pricing
Flat roof replacement cost calculator
TPO, EPDM, PVC, and built-up — “flat roof” covers four different membrane systems with different price points and lifespans. Pick the wrong one and you'll replace it in 12 years.
Typical 2026 ranges
- TPO / PVC membrane: $550–$1050 per square (installed)
- Lifespan: 25 years (TPO); EPDM 25–30; PVC 25–30; built-up 20.
- Vs. pitched asphalt: Similar per-square cost, but simpler geometry usually means lower total.
TPO vs. EPDM vs. PVC vs. built-up — pick the right membrane
- TPO (thermoplastic polyolefin): White, energy-efficient, most popular today. $5.50–$10.50/sq ft. 20–25 year lifespan. Seams heat-welded.
- EPDM (rubber): Black rubber sheet, proven since the 1970s. $4.50–$9/sq ft. 25–30 year lifespan. Seams glued/taped — more failure-prone than welded.
- PVC: White, chemical-resistant (good near kitchen exhausts/restaurants). $7–$12/sq ft. 25–30 year lifespan. Heat-welded seams.
- Built-up (tar and gravel / BUR): Layered bitumen + gravel. $5–$9/sq ft. 20-year lifespan. Heavy, but tough.
- Modified bitumen: Asphalt + rubber rolled in sheets, torched or self-adhered. $4–$8/sq ft. 15–20 year lifespan.
Why flat roofs leak more than pitched (and what prevents it)
Flat roofs don't shed water — they drain it. That makes three things matter more than on a pitched roof:
- Slope to drains:Even “flat” roofs need 1/4″ per foot minimum slope. Tapered insulation is how you achieve it — expect $3–$6/sq ft added.
- Drains, scuppers, and parapets: Clogged drains cause 90% of flat-roof leaks. Bid should include drain cleaning + new strainers.
- Seam quality: Heat-welded (TPO/PVC) beats glued (EPDM) for longevity. Ask to see the welder certification.
Overlay vs. tear-off
Most building codes allow up to 2 roof layers on a flat roof. An overlay can save $2–$4/sq ft, but you lose the chance to inspect the deck — if moisture is trapped underneath, you're buying a slow leak. Tear-off is usually worth it.