Pros and Cons of Different Flat Roof Systems

General Roofing Systems Canada Repairs flat roofs throughout Canada. Flat Roof Repair; Calgary, Red Deer, Edmonton, Fort McMurray, Lloydminster, Saskatoon, Regina, Medicine Hat, Lethbridge, Canmore, Banff, Cranbrook, Kelowna, Vancouver, Whistler, Winnipeg, Toronto and points between. British Columbia. Alberta. Saskatchewan. Manitoba. Ontario.

Below you will find the pros and cons of each type of flat roofing system we offer written by our Alberta roofing repair crew. A link has also been provided below to our main website describing each.

Spray Foam

While moderately low in price, this is largely based only on individual perceptions. As far as material efficacy goes, spray foam is seamless and light. However, in Canadian weather, it is subject to cracking due to extreme hot/cold shifts, and a failure can result in a complete re-roofing being required. As well, maintenance mandates top-coating, which contributes to expenses – nullifying perceptions about spray foam being a low cost solution.

Single-ply Systems (EPDM/PVC/TPO)

While these have been excellent systems in terms of performance and a lower initial price, they do not have the longevity of 4-ply tar and gravel or 4-ply liquid rubber. As well, these systems are vulnerable to tearing over time. The installation process also entails using mechanical fasteners, which provides another damage vector with respect to water and strong weather conditions.

Tar and Gravel

A seamless and versatile system, which also has a long life if maintained properly. However, the installation process can be quite messy. As far as maintenance goes, leaks can be difficult to find. As a result, maintenance costs are higher than single-ply systems and liquid rubber application. Maintenance or repair with tar and gravel systems often entails a vacuuming as well if damaged sites are difficult to locate.

SBS Torch-on

This system is lighter than 4-ply and has a broad range of application methods. However, torching is not seamless and the life cycle is shorter than 4-ply systems. A fire watch is also required during installation, which contributes to a higher price point.

Liquid Rubber

Seamless, UV stable, and elastic, this is a system which we have had a lot of success with in the Canadian climate. The 1000% expansion rate provides a “cushion” for extreme weather changes, which makes it resilient to tearing and leaks. The system is also multi-purpose, having applications in gutters, too.¬†However, the price point is initially higher. In terms of total life cycle cost, it is similar to all other systems.


We usually recommend single-ply systems and liquid rubber to our clients. Single-ply systems are more economical on the front-end and perform well. Liquid rubber also has the least chance of failure, as it is the most predictable and is 4-ply. Also, it is the system most suited to Canadian weather due to its elasticity.

For more information about each system we have described, visit our main site by clicking here for more information on flat roofing.

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