Everything About Torch Down Roofing

With so many different roof types in SoCal, let alone the entirety of the States, roofing is complicated. Shingles are better if you have a pitched roof, but they are a big no-no for flat roofs. Instead, there’s a set of materials that’s excellent for roofs with minimal or no pitch. One of these is torch down roofing.

Torch down roofs are used throughout the world, and they come with their set of pros and cons. With that said, we’ll take a look at everything you need to know about torch down roofs. For now, let’s check out what they actually are.

Torch down roofing

What Is Torch Down Roofing

Torch down roofing is the name of the application process of modified bitumen layers on your roof. During this, a propane torch is used to fuse these layers, which is where their name derives from.

Types Of Torch Down Roofing

There are two main types of torch down roofs, depending on the number of layers used.

  • 2-Layer System: The two-layer system consists of a base and cap sheet, which are sealed to the roof’s underlayment with the help of an open-flame propane torch.
  • 3-Layer System: While practically identical to the two-layer one, this system has an extra sheet of granules, which add to the roof’s durability.

That being said, apart from having two application processes, torch down roofing materials may vary.

What Materials Are Used in Torch Down Roofing

At its core, the material used is modified bitumen, which is asphalt-based and has some added materials. The two most common additives are Atactic Polypropylene (APP) and Styrene Butadiene Styrene (SBS).

APP is a form of plastic, while SBS is a form of rubber. SBS is considered the best of the two because of its added flexibility and lower melting point. On top of that, SBS modified bitumen sheets can be installed with the help of adhesive or through a cold process.

Apart from this, these roofing layers also contain a few other materials to ensure the best installation and durability. These include a sheet of polyester or fiberglass, a thermofusible film, and a granule layer.

Torch Down Roofing Pros and Cons

Like every flat roof material, torch down roofing comes with its pros and cons.


  1. Flexibility: Due to their composition, the material expands during the scorching SoCal summers and contracts once the temperatures drop. In turn, they’ll be no cracks or layers melting, enhancing your roof’s longevity.
  2. Practically Waterproof: When properly installed, torch down roofing will keep the seams sealed, making your roof virtually water-resistant. However, you’ll need to have your roof checked and repaired every few years, to ensure that it remains waterproof.
  3. UV Protection: By utilizing a top sheet of granules, your new roof will reflect UV rays, thus increasing their durability and keeping the electricity bill lower than ever before.
  4. Easy To Install: Torch down roofing is pretty straightforward to install. All you need is the modified bitumen sheets, a propane torch, and safety equipment.


  1. It is dangerous to install: While they’re easy to install, torch down roofs are notorious for being dangerous, especially when you opt for the DIY way. Make sure to get expert help if you’ve never done your roofing before.
  2. Water can get trapped between the layers. That’s why their installation must be done in dry weather conditions to ensure that it lasts for a long time.

How to Install a Torch Down Roof

Torch down roofs are very easy to install. The process is straightforward as long as you have all the necessary safety equipment and obtain the modified bitumen sheets.

Once you’ve laid the insulation and underlayment, you’ll just have to place the base sheet and follow it up with the cap sheet. When you seal these two together using the propane torch, you can add a granule layer or keep it as is.

How Long Does Torch Down Roofing Last

If you choose the DIY option, torch down roofing will last about 10 years. In general, these roofs have a lifespan of 15-20 years if properly installed, with some lasting for up to 30 years.

However, this all comes down to how often you have your roof checked and repaired.

We’ll Take Care of Your Torch Down Roof Repair

While torch down roofs are widely used and are one of the best options for flat roofs, they are often not treated well. Whether it’s due to bad installation or lack of maintenance, your torch down roofing might not last as long as you wanted it to. Here’s where we come into play!

At Roofing Wise, we’ll ensure that your new roof will last for a long time and is installed properly. We’ll also take care of its maintenance and any required torch down roof repairs.

Call us now at (833) 315-7663 for a free estimate!

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