Which is the best membrane to install for my flat roof?

At Crest Roofing, we often get asked which roofing membrane is the best system to install.

Many years ago we used to give the customer only two choices: Tar and Gravel (T&G) or SBS (commonly known as Torch-On).

Over time new products have emerged to share the market. Today we can add PVC, TPO, EPDM, hot rubber type flood coats and spray foam type systems.

I am a firm believer that manufactures of certain roof systems should show proof that their product/products will in fact last the said 20 or 25 years they state. I don’t believe in weather room simulators.

Our Canadian weather is probably one of the harshest climates one will come across. We have extreme cold winters (-25 to -40) mixed with Chinooks that can go as high as (+10) all in 24 hours. This is very hard on membranes of any kind.

Snow melting, turning to ice, and continually repeating the cycle is hard on your membrane as well. Ice is always pushing and prying. Summers can get as hot as plus 37° degrees Celsius, and very dry!

I am a Tar and Gravel/SBS guy from way back. Some of these T&G roofs can last up to 35 or 40 years with a good installation and preventative maintenance. To say all T&G roofs will last this long is a far stretch. I am just stating what I have come across in my 30+ years of experience.

SBS was introduced to the Edmonton Roofing Companies in the mid 1970’s through pool construction. A manufacturer called Soprema was making this product in a place called Strasbourg, France, and soon opened up a plant in Quebec, Canada.

I was trained to install this product around 1983. This product took a while to catch on, but by the mid 1990s it became very popular. Roofing inspectors loved this new roofing system, and soon convinced school boards, government, and commercial property owners that this was the way of the future.

So, tar and gravel took a backseat. Other manufacturers followed this trend; IKO has been making a very good equivalent product with equal warranty. The end result is both manufacturers back and support their products to very strict architectural standards.

Today, both SBS and Tar and Gravel for Edmonton roofing seem to be holding up well to the Canadian climates. The proof is in the pudding. T&G is a little tougher to find leaks and repair. One has to be a very experienced and a qualified roofing installer to be successful at T&G repairs.

SBS on the other hand, makes it easy to see the deficiencies as it is not covered in gravel. Simply spot the ridge, bridging, blister or hole, cut out the affected spot, prime with an asphalt-based primer and re-torch one or two plies of same product.

Other new products that have come out in the last 20 years stating that their product is better are up for a little criticism. As an experienced Edmonton roofing contractor, and most would agree, I feel that the jury is still out on some of these other products.

Each membrane has its purpose in the Edmonton roofing industry.

Big open warehouses with little equipment on the roof are more suited for an EPDM system.

Sun decks with living space underneath, a good quality PVC or SBS will do. Sarnafil Canada installed their system on the old Maple Leaf Gardens, the Blue Jay’s Skydome, and the Saddle Dome in Calgary. They make specialized deck membranes as well.

One product our company uses for EPDM is Firestone, a company that’s been around a very long time. TPO is a single ply membrane; it is a combination of rubber and PVC. I won’t throw this membrane under the bus, as I feel manufacturers have put a lot of effort into making this product competitive. Inspectors and architects have been pushing this product as well, so a good qualified installer should be able to make this product perform!

As roofing experts in Edmonton, we generally look at every roof to see what product will suit you best. So Google away and consult with a reputable roofing company or an accredited roofing inspector for more information.

Don’t forget to ask roofing companies for proper credentials, like liability insurance (open flame, if SBS or T&G) and WCB.


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