How the three differ in practice
The seam difference is the most consequential. A heat-welded seam fuses the sheets into a single mass; an adhesive or taped seam bonds them. Both work when done correctly, but they age differently and they fail differently, and seams are where membranes fail.
| EPDM | TPO | PVC | |
|---|---|---|---|
| Material | Synthetic rubber | Thermoplastic polyolefin | Polyvinyl chloride |
| Seams | Adhesive or seam tape | Heat-welded | Heat-welded |
| Typical colour | Usually black; white available | Usually white or light | Usually white or light |
| Chemical and grease resistance | Poor against oils and greases | Moderate | Good — often specified near kitchen exhaust |
| Cold-weather installation | Adhesives are temperature-sensitive | Welding is less temperature-dependent | Welding is less temperature-dependent |
| Repair | Straightforward with compatible materials | Weldable, but the specific product matters | Weldable, but the specific product matters |
| Track record | Longest field history of the three | Shorter, and formulations have changed | Long history in specific applications |
The question that matters more than the material
Attachment is also what makes leak location hard. On a mechanically fastened assembly, water beneath the sheet can travel a long way from its entry point before finding a path through the deck, which is why locating a leak on a low-slope roof requires investigation rather than a guess.
For most buildings the practical decision is made by what is already there, what the deck and insulation allow, how many layers exist, and what the code position is on recovering. The membrane brand is usually the last decision rather than the first.
- Attachment method, and why it was selected for this building
- Insulation type, thickness, and whether taper corrects the drainage
- Whether a cover board is included — an easy place to trim a bid
- How many existing layers there are and what the code allows
- Which warranty is offered: manufacturer system, material only, or workmanship
Where each tends to be chosen
EPDM has the longest field history and is straightforward to repair with compatible materials, which matters on a building you intend to hold. Its weakness is chemical resistance — oils and greases degrade it, so it is a poor choice near kitchen exhaust.
TPO and PVC are heat-welded and usually light-coloured, which reduces summer heat gain. PVC's grease resistance makes it common on restaurant and food-service buildings. TPO formulations have changed over the years, which is a reason to ask about the specific product and its track record rather than the category.
Published August 20, 2026 and last reviewed August 16, 2026 by Greater Burlington Roofing. General roofing information; an on-site inspection is required for property-specific recommendations.