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The TPO & EPDM Roof Cost Calculator prices a low-slope membrane roof the way a commercial estimator does: membrane, attachment method, insulation and tear-off as separate line items. Pick TPO 60 or 80-mil, EPDM 60 or 90-mil, PVC 60-mil or modified bitumen, choose mechanically fastened, fully adhered or ballasted attachment, add the insulation R-value you plan to install, and the tool returns installed cost per square foot, per square, and a total project range. Installed TPO typically runs $5-$9 per sq ft for 60-mil, EPDM $4.50-$8, and PVC $7-$12, with polyiso insulation adding $2.60-$4.60 per sq ft. Most of the difference between competing flat roof quotes comes from membrane thickness, insulation R-value and attachment method, so write the assembly into the contract before comparing prices. Pair with our Flat Roof materials calculator, Roof Coating calculator and Insulation calculator.
TPO is a single-ply white membrane with heat-welded seams, and it has become the default on commercial low-slope roofs. It is priced per square installed, and the insulation below it is frequently a larger line than the membrane itself.
| Roof size | Area | Squares | Rolls at 10 ft x 100 ft |
|---|---|---|---|
| 2,000 sq ft | 2,000 sq ft | 20 | 2.2 |
| 4,000 sq ft | 4,000 sq ft | 40 | 4.4 |
| 6,000 sq ft | 6,000 sq ft | 60 | 6.6 |
| 10,000 sq ft | 10,000 sq ft | 100 | 11 |
| 20,000 sq ft | 20,000 sq ft | 200 | 22 |
A low-slope roof is measured flat, so there is no pitch multiplier — but add roughly 10% for seam overlaps, and more for a roof with many penetrations.
| TPO | EPDM | PVC | |
|---|---|---|---|
| Colour | White, reflective | Black, absorbs heat | White, reflective |
| Seams | Heat-welded | Adhesive or tape | Heat-welded |
| Grease resistance | Moderate | Poor | Best |
| Cooling load | Lower | Higher | Lower |
| Field repair | Weld — needs equipment | Patch — easy | Weld — needs equipment |
| Relative cost | Mid | Lowest | Highest |
The drainage and the insulation, not the membrane brand. A roof that ponds fails at the ponding regardless of what is on it, and wet insulation under a sound membrane keeps a building damp and expensive to heat. Get the fall right first.
A single-ply white thermoplastic membrane with heat-welded seams, used on low-slope and commercial roofs. The white surface reflects heat, which lowers cooling load.
It is reflective where EPDM is black, and its heat-welded seams are stronger than EPDM's adhesive ones. EPDM is cheaper and far easier to patch in the field. Neither is better in every case.
Typically 20 to 30 years installed well and drained properly. Ponding water shortens that substantially, which is why the fall matters more than the membrane brand.
Frequently the insulation rather than the membrane — particularly tapered insulation, which is how fall is built into a deck that has none of its own.
Gluing down a rubber roof yourself? The EPDM rubber roof calculator lays out the sheets and counts adhesive pails and seam tape.
Pricing a garage or porch? The flat roof and rubber roof cost calculator has a worked estimate and costs by roof size.
TPO on an RV? The RV roof replacement cost calculator prices it per foot of coach.
Comparing with modified bitumen? The torch down roof cost calculator uses HomeGuide's 2026 APP and SBS prices.
A silicone coat can add 10–15 years to a sound membrane. Compare the roof coating cost before tearing it off.
Need the whole roof at once? The free roofing calculator works out roof area, squares, shingle bundles, underlayment, drip edge, ridge cap and installed cost from one set of measurements.