What is Torch On Roofing and why use it?

Torch On roofing is made up of two layers of modified bitumen that are melted together by a torch- hence the name. This creates a roof that is resistant to ultraviolet light and a waterproof barrier, ideal for the Lower Mainland’s wet season.

The Torch On roofing system, is usually used for flat roofs where snow, rain and/or ice can easily collect and sit for long periods of time. It covers the entire roof at a thickness of approx 4 mm.

Types of Torch On Roofing:

Torch On roofing is available in a two-layer or three-layer system.

  • The two-layer torch On roofing system is usually made up of a smooth base ply and one ply with a granular surface.
  • The three-layer torch On roofing system has an asphaltic board, a smooth base ply, and a top ply with a granular surface. The three-ply roof is better and lasts longer than the two-ply system.

Benefits of a Torch On Roof:

The major advantage of Torch On roofing, apart from its waterproof barrier, is its durability. A Torch On roof lasts around 20 years and is virtually maintenance free, during that time. Torch On roofing provides many of the same benefits of traditional tar and gravel roofs. However, Torch On doesn’t use a gravel ballast. That means the roof is lighter and there’s no gravel to clog up drains or eavestroughs.

Torch On Roof - Whonnock Roofing and GuttersIn recent years, with improved technology, prices have come down and quality has gone up, meaning Torch On is a more viable option for homeowners. Maintenance costs are also very low for this type of roof. A Torch On roof also provides strength and flexibility to a homeowner.

Roof Maintenance

No matter what roofing material you choose, maintenance is key to keeping your roof working properly and increase its longevity.

If you get a leak, it’s important that you repair it as soon as possible. Try to check your attic every few months for water damage. You might not catch a leak right away, but the sooner you do find the leak the better. Don’t wait until it becomes a huge problem. Remove any debris build up on the roof – especially if you have a flat roof. When monitoring your roof, always check the protrusions on your roof. They are the areas around the chimney, around your gutters and around your flashing details. These are all areas that may require repair over your roof’s lifespan.


Believe it or not, the installation of Torch On roofs does not always require the removal of an existing roof. If your current roof is in decent shape, you can likely install a Torch On roof over top but if not, it is recommended that you remove it so you ensure the new Torch On roof lasts as long as possible.

Torch On Roof - Certified Installation Whonnock RoofingInstallation of a Torch On roofing system requires knowledge and experience using a blowtorch. Using this type of tool to install a Torch On system calls for the right type of materials and insulation to ensure that the torch does not damage the overall structure. The application process should not be exposed to any type of adhesives or solvent-based materials and should only be performed by those who understand the dangers behind using a torch. This method should be able to provide a secure, leak-proof seal; however, if it is not done correctly, it could cause more problems than it’s worth.

The roof then needs to be covered by a layer of fiberglass felt. This is nailed to the roof to secure it. This becomes the base sheet for the roofing material to be joined. This base sheet needs to cover the roof smoothly.

The bitumen layer is rolled out onto this base layer. While it is rolled out, a torch is used to melt the material so it adheres to the base. The roll is moved forward, and the bitumen layer pressed down to get a good seal. To get a good seal on metal flashings, such as around vents and chimneys, a primer or other similar material is applied to the metal surfaces before covering it with the roofing layer.

Finding a Professional Roofing Company

Torch On Roof - Certified and Experienced Installation Whonnock RoofingTorch On roofs provide a strong, waterproof seal that will last for many years, with very little maintenance or upkeep needed. While they are not as popular as they once were due to the dangerous application, many homeowners still prefer the classic method of installing a two or three-ply Torch On roof.

Since installation can be hazardous, it’s important to find the right roofing company to do the job. It’s very easy to make a mistake while applying torch on materials to a roof. Materials can be accidentally overheated and cause a fire that can quickly spread throughout the dry, hot attic area. Be sure to check that the company doing your Torch On roof has the proper fire insurance in place and that they also carry ticketed/certified flat roofers.

Here at Whonnock Roofing and Gutters we carry all the necessary liability/fire insurances. We also have ticketed torch on roof installers to make sure that you get a top notch job. Call us today for your free, no hassle quote!