Five systems, one question: which fits your roof?
Flat roof materials
Most flat roofs in Ontario are one of five types. Each behaves differently in a freeze–thaw winter, on a busy rooftop, or under a rooftop deck. Start here to see how they compare, then open the page for the one you have or are considering.
- EPDM
- TPO
- PVC
- Torch-on and SBS
- Tar and gravel
Pick a material
EPDM (rubber)
Black synthetic rubber in large sheets. Few seams, easy to patch, common on houses and small commercial roofs.
View details
TPO (white membrane)
Heat-welded white single-ply. Reflective, popular on commercial buildings with a lot of roof area.
View details
PVC
Heat-welded single-ply that handles grease, chemicals and heavy rooftop traffic better than most.
View details
Modified bitumen (torch-on or SBS)
Asphalt-based rolls in two or more layers. The usual choice for Toronto-style house roofs and tight details.
View details
Built-up roofing (tar and gravel)
Layers of felt and bitumen, often topped with gravel. Older buildings have it; some owners still choose it.
View detailsSide-by-side comparison
| EPDM | TPO | PVC | Modified bitumen | Built-up (BUR) | |
|---|---|---|---|---|---|
| Looks like | Black rubber sheet | White or grey sheet | White or grey sheet | Dark granulated or smooth rolls | Black tar with gravel |
| How seams join | Tape or liquid adhesive | Hot-air welded | Hot-air welded | Torched, self-adhered or cold-applied laps | Overlapped felts set in bitumen |
| Common attachment | Fully adhered, ballasted or fastened | Fully adhered or fastened | Fully adhered or fastened | Torched, self-adhered or cold adhesive | Hot or cold-applied layers |
| Typical service life | 20 to 30 years | 15 to 25 years | 20 to 30 years | 15 to 25 years | 20 to 30 years |
| Starting price | from $8 per sq ft | from $9 per sq ft | from $11 per sq ft | from $8 per sq ft | from $9 per sq ft |
| Often chosen for | Houses, garages, small commercial | Large commercial roofs | Restaurants, labs, rooftop traffic | Houses, townhouses, tight flashings | Replacing an existing BUR |
| Repair by patching | Easy | Moderate, needs welding or adhesive | Moderate, needs welding | Easy to moderate | Moderate, messy |
Service lives are common ranges, not promises. Maintenance, drainage and the quality of the install matter as much as the membrane.
How to choose without a sales pitch
Start with the building, not the product. A flat rear roof on a Toronto semi, a condo podium deck and a warehouse the size of a football field call for different things. The deck underneath (wood, concrete, steel), how much foot traffic the roof gets, what the roof drains do in spring melt, and what is already up there all narrow the field before price comes into it.
Then look at the details. Most leaks start at flashings, drains and penetrations, not in the open field of the membrane. A system that is easy to flash around your chimney, vent stacks and parapet walls is often worth more than a few cents per square foot saved on the main sheet.
The guide to choosing a flat roof material goes through this step by step, and the replacement page explains what a full tear-off or recover involves.
Starting prices by material
| Item | Starting price |
|---|---|
| EPDM roof replacement | from $8 per sq ft |
| TPO roof replacement | from $9 per sq ft |
| PVC roof replacement | from $11 per sq ft |
| Modified bitumen (torch-on or SBS) replacement | from $8 per sq ft |
| Built-up (tar and gravel) roof replacement | from $9 per sq ft |
Starting prices in CAD before 13% HST, based on typical Ontario contractor rates (mostly Toronto and the GTA). The final price depends on roof size, access, the layers to remove, the membrane, drains and flashings, and is confirmed in your written quote.
See the full pricing page for repairs, inspections and coatings.
Questions about flat roof materials
Can I put a new membrane over my old flat roof?
Sometimes. A recover (new membrane over the old roof) works only if the existing layers are dry and the deck is sound. A moisture scan during an inspection tells you whether it is an option.
Which material suits a house with a small flat roof?
EPDM and modified bitumen are the usual choices for houses, garages and additions because they are practical to install on small, cut-up roofs with many details.
Does a white roof matter in Ontario?
Reflective roofs reduce summer heat gain, which helps buildings with rooftop air conditioning. For a house roof in a cold climate the difference is small compared with drainage and flashing quality.
Can different membranes be mixed on one roof?
Not directly. Many membranes are chemically incompatible with each other and with old asphalt, so transitions need a proper termination detail or a separation layer.
Leak, damage or an old flat roof?
Send a few details and photos. We reply by email with next steps and a written quote.