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Flat Roof Cost Calculator
Flat roof replacement costs $4,000–$16,800 installed in 2026 (about $3–$11 per sq ft). A built-up roof (BUR) runs $4,500–$12,600; an EPDM rubber membrane $4,500–$16,000; TPO $7,700–$14,000. Labor is roughly 60% of the job, and tearing off an old membrane adds cost. Use the calculator below for a figure matched to your roof.
Educational calculators — always consult a licensed professional before making financial decisions.
Small garage, carport, or addition. Typical for detached structures.
White thermoplastic membrane. Energy-efficient (reflects heat), weldable seams, most widely installed today.
Clean deck or minor wear; no significant removal needed.
Current roof drains are properly sized and positioned. No additional plumbing work needed.
Total flat roof cost
$3,300 – $5,400
600 sq ft — 15–25 years lifespan
Cost Breakdown
Where Your Money Goes
Your Selections
Flat roof costs vary significantly by material, membrane thickness, and existing roof condition. Professional installation recommended for all flat roof systems.
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What you'll need
- ·Roof area in square feet
- ·Material preference — TPO, EPDM, modified bitumen, or PVC
- ·Whether existing roofing needs to be removed
- ·Residential or commercial building type
What you'll get
- ✓Total roof cost — Materials + labor
- ✓Cost per square foot — By material type
- ✓Material comparison — TPO vs EPDM vs PVC vs bitumen
- ✓Tear-off cost — If removal is needed
How it works
Enter roof area
Measure the total flat or low-slope roof area in square feet.
Select membrane type
Choose TPO, EPDM, modified bitumen, PVC, or built-up roofing.
Add tearoff & insulation
Old membrane removal and new insulation board are common add-ons.
2026 Flat Roof Cost by Membrane
| Membrane | Typical Total (installed) |
|---|---|
| Built-up roof (BUR) | $4,500–$12,600 |
| EPDM rubber membrane | $4,500–$16,000 |
| TPO membrane | $7,700–$14,000 |
Full replacement by membrane type, typical flat roof, installed. National average estimate for 2026 (~$3–$11 per sq ft).
Methodology & sources
The cost figures on this page are generated from a single, sourced cost-data file (Full replacement by membrane type, typical flat roof, installed. National average estimate for 2026 (~$3–$11 per sq ft).). Labor is roughly 60% of a flat-roof job. Tear-off of an old membrane, insulation, and drainage work add to the total. Last verified July 2026.
- HomeGuide — Flat Roof Replacement Cost (2026) — retrieved 2026-07-13
- HomeGuide — Rubber (EPDM) Roof Cost (2026) — retrieved 2026-07-13
- Angi — EPDM Roofing Cost (2026) — retrieved 2026-07-13
Frequently asked questions
How much does a flat roof cost?+
Flat roof replacement costs $4,000–$16,800 installed for a typical flat roof — roughly $3–$11 per sq ft depending on membrane. A TPO (thermoplastic polyolefin) membrane runs $7,700–$14,000 installed and is the most popular choice. EPDM rubber runs $4,500–$16,000 installed. A built-up roof (BUR) runs $4,500–$12,600 installed. PVC sits at the top of the range and offers the best chemical resistance.
What is the best flat roof material?+
TPO is the most popular choice due to its balance of cost, durability, and energy efficiency — white TPO reflects heat, reducing cooling costs. EPDM (rubber) is durable and budget-friendly but less energy-efficient. PVC is best for roofs with kitchen exhaust or chemical exposure. For low-slope roofs in moderate climates, TPO or EPDM typically offer the best value.
How long does a flat roof last?+
Flat roof lifespan varies by material: TPO lasts 15–25 years, EPDM lasts 20–30 years, PVC lasts 20–30 years, and modified bitumen lasts 15–20 years. Proper installation, drainage, and annual maintenance (clearing debris, checking seams and flashing) significantly extend lifespan.
Do flat roofs need drains?+
Yes — all flat roofs need a drainage system. Options include interior drains (most effective, requires piping), scuppers (openings in the parapet wall), and gutters with a slight slope (2% minimum). Poor drainage is the leading cause of flat roof failure. Budget for drainage work as part of the job — cost depends on roof size and system type.
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Back to the calculator ↑Flat Roof Cost Calculator is built and maintained by the RealCostIQ editorial team. Cost ranges and rates are checked against published industry data and contractor quotes, and revised when the underlying figures move. Read our data methodology or more about who builds this. Every calculation runs in your browser — no account, and none of your inputs are stored.
Cost ranges and rates here are checked against contractor quotes and published industry data. If a number still looks off, email Support@RealCostIQ.com and we'll review and fix it.