Roofing · Compare
TPO vs PVC membrane: which single-ply to spec for a low-slope roof
Both are heat-welded thermoplastics, but grease and chemical exposure is the one condition that forces PVC over TPO.
Short answer
Pick PVC when the roof sees grease or chemical exposure, and pick TPO for a reflective cool roof at moderate cost where there is no grease. That single condition, chemical exposure, is the biggest deciding factor between these two heat-welded thermoplastics. TPO is specifically not resistant to animal fats and cooking oils, so a TPO roof on a restaurant commonly fails in eight to twelve years, while PVC resists fats, oils, and industrial chemicals long-term. Absent that exposure, both weld into strong seams and the call comes down to budget, reflectance requirement, and warranted life.
TPO membrane vs PVC membrane: side by side
| Factor | TPO membrane | PVC membrane |
|---|---|---|
| Family and seam | Thermoplastic, hot-air welded seams that fuse into one material | Thermoplastic, hot-air welded seams that fuse into one material |
| Chemical and grease resistance | Poor; degraded by animal fats and cooking oils | Excellent; resists fats, oils, and industrial chemicals |
| Reflectivity | High, white, SRI commonly above 90 | High, white, SRI commonly above 90 |
| Upfront installed cost | Middle; roughly 7 to 10 dollars/ft2 (verify locally) | Usually highest; roughly 8 to 12 dollars/ft2 (verify locally) |
| Aging mechanism | Modern formulations improved; longest field data still shorter than EPDM | Good, but plasticizers can migrate out over decades, leading to cold cracking |
| Substrate over asphalt | Compatible; check manufacturer rules | Not compatible with asphalt; needs a separator sheet or cover board |
| Standard / spec | ASTM D6878 (TPO sheet) | ASTM D4434 (PVC sheet) |
| Best use | Reflective cool roof, moderate cost, no grease exposure | Restaurant, kitchen, and industrial-chemical roofs |
Which should you pick?
Choose TPO membrane when
- The roof needs a reflective cool roof to meet an energy code or reduce cooling load, with no grease exposure
- Budget is the constraint and PVC's premium is not justified by the exposure
- You are recovering over an asphalt or mod-bit roof and want to avoid PVC's separator requirement
- You want a welded, repairable membrane for a warm-climate commercial building
Choose PVC membrane when
- The roof has rooftop kitchen exhaust, grease-laden discharge, or industrial chemical exposure
- The building ponds water and you want a membrane comfortable with standing water
- The small cost premium over TPO buys chemical resistance and a longer thermoplastic track record
- You need a welded reflective roof but the exposure rules TPO out
Bottom line
It depends on chemical exposure. If the roof sees grease, cooking oils, or industrial chemicals, PVC is the only durable choice of the two and TPO is off the table, full stop. Without that exposure, both are proven white thermoplastics with welded seams, and TPO is the lower-cost path to a reflective cool roof. The TPO-to-PVC price gap has narrowed over the past decade, so when PVC costs only a little more, its chemical resistance and longer field history can be worth the premium even on a roof without heavy grease. In every case, installation quality and the warranted term move real lifespan more than the chemistry does, so price installed cost against warranted life and confirm the assembly against the manufacturer's system.
FAQ
Is TPO or PVC better for a restaurant or grease roof?
PVC, and it is not close. PVC resists animal fats, cooking oils, and chemicals that break down TPO. Rooftop exhaust puts a grease film on the membrane daily, and TPO on a grease roof commonly fails in eight to twelve years as the oils soften and swell the polymer. Grease containment helps but does not change the membrane decision, so specify PVC where grease or chemicals are present.
Is TPO or PVC cheaper?
TPO is usually the lower cost of the two, with recent installed figures around 7 to 10 dollars per square foot versus roughly 8 to 12 for PVC, though ranges overlap by region and roof complexity. The gap has narrowed over the past decade. Material is the smaller part of installed cost anyway; labor, attachment, and insulation drive the total, so the cheaper membrane on paper is not always the cheaper finished roof.
Can you install PVC or TPO over an old asphalt roof?
TPO can go over asphalt subject to the manufacturer's rules, but PVC cannot be in direct contact with asphalt or bituminous materials. PVC's plasticizers react with and dissolve the asphalt, and the membrane loses the plasticizer it needs to stay flexible. To recover with PVC over a built-up or mod-bit roof, install a separator sheet or cover board between them, as NRCA and the manufacturers require.