Cost by material type
| Material | Per sqft | 2,000 sqft |
|---|---|---|
| TPO (Thermoplastic Polyolefin) Most popular commercial flat roof. White surface reflects heat. 15-25 year lifespan. | $5–$9 | $10,000–$18,000 |
| EPDM (Rubber Membrane) Budget rubber membrane. Black or white. 15-25 year lifespan. Common on residential flat roofs. | $4–$8 | $8,000–$16,000 |
| Modified Bitumen Multi-ply asphalt system. Best for roofs with foot traffic. 15-20 year lifespan. | $5–$10 | $10,000–$20,000 |
| Built-Up Roofing (BUR) Tar and gravel — old school but durable. 15-30 year lifespan. | $6–$12 | $12,000–$24,000 |
| PVC Membrane Premium single-ply. Chemical resistant, hot-air welded seams. 20-30 year lifespan. | $6–$11 | $12,000–$22,000 |
Planning estimate
$14,000
A reference midpoint, not a bid. Real quotes vary by pitch, access, and local labor — get at least three estimates from licensed, insured roofers before deciding.
FAQ
How much does a flat roof replacement cost?
A flat roof replacement costs $8,000–$24,000 for a 2,000 sqft roof. TPO and EPDM are the most common — $4–$9/sqft. PVC is premium at $6–$11/sqft. Modified bitumen and BUR cost more but handle foot traffic better.
Which flat roof material lasts longest?
PVC membranes last 20–30 years with proper maintenance. TPO and EPDM typically run 15–25 years. Modified bitumen lasts 15–20 years. Ponding water is the #1 killer — any flat roof needs proper drainage to reach its lifespan.
Can I put a new flat roof over the old one?
Sometimes. If there's only one existing layer and the decking is solid, you can overlay. But most manufacturers require a tear-off to honor their warranty. Overlay also traps moisture between layers — if the old roof has any leaks, removal is mandatory.
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