All About Torch Down Roofing

D.P. Taylor
Written by D.P. Taylor
Reviewed by Ami Feller
Updated July 28, 2022
Man torch down roofing
Photo: Nenov / Getty Images


  • Torch down roofing involves heating sheets of modified bitumen.

  • The sheets bond together to form a waterproof and fire-resistant seal.

  • Torch down roofing is best used on flat and low-slope roofs.

  • The pros are that it’s low cost and low maintenance.

  • The cons are that it’s easily damaged and tricky to install.

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Roofing is a little more complicated when you have a roof with very little pitch to it. In situations like this, you can't just install ordinary shingles, so you should explore alternatives.

Torch down roofing is one of those options. It's a unique roofing method that will give your roof a beautiful finish and waterproof protection. Here's what you should know about this method, including how much it costs and its pros and cons.

What Is the Torch Down Roofing System?

Torch down roofing involves laying out sheets of modified bitumen—a material that is used as a binder in asphalt—and then using a hand-held propane torch to heat the material so it bonds permanently with the roof. The bitumen used for this type of roofing is typically modified with rubber or plastic, which means it can expand and contract without resulting in any damage.

This type of roofing is used most commonly on homes with flat roofs or at least ones with a very slight pitch, as opposed to the steep pitched roofs most homes have.

The reason you would use this type of roofing instead of standard shingles for a flat roof is that shingles are meant to assist a roof in draining water quickly and efficiently. If there is no slope, the water will start to pool and may find a way through the cracks and crevices of the shingles. But with torch down roofing, there’s a watertight seal between the bitumen sheets.

How to Properly Maintain Torch Down Roofing

You can protect torch down roofs by coating them to protect from ultraviolet rays, and you will need to reseal it every few years. Other than that, there's not much that needs to be done to maintain the roof aside from clearing off debris regularly and patching any holes that develop.

What Are the Pros of Torch Down Roofing?

Torch down roofing has a lot of great pros that make it an attractive option for some homes.

Saves Energy

White or light-colored bitumen sheets reflect sunlight, which means your home will be cooler and more energy efficient. The darker the color, though, the more heat it absorbs.

Durable and Lightweight

Bitumen sheets are very light, weighing just 2 pounds per square foot. But they are also strong, so they’re good at protecting your home from the elements (they do not stand up as well to blunt force damage, however).

Easy Maintenance

Little needs to be done to maintain torch down roofs other than patching holes and clearing off debris. As a result, you won’t have to spend much time or money on maintenance.

Low Cost Installation

Torch down roofing costs around $7,000, which is less than other roofing options like metal or tile. 

Fire and Leak Resistant

Torch down roofs provide an excellent seal against water leaks, and they’re fire-resistant as well—so they offer homeowners peace of mind.

What Are the Cons of Torch Down Roofing?

There are a few cons you should be aware of before choosing this roofing.

Not Suitable for Angled Roofs

A torch down roof is generally best for homes with a slightly angled roof; it’s not an appropriate option for steeply pitched roofs. Most pros recommend it for roofs between .5:12 and 2:12 pitch.  If the roof is perfectly flat, the modified bitumen will leak because it’s not made to handle ponding water. 

Can Be Damaged By Impact

Unfortunately, while this material can stand up well to water, fire, and UV rays, it is more easily damaged by, say, a falling tree branch or hail. This can create holes in the roofing material and eliminate its waterproof barrier. Fortunately, it's fairly easy to patch holes, but it can be a hassle and may affect the appearance of your roof.

Tricky to Install

Installing torch down roofing takes some skill and expertise, so it's something you'll want to hand off to the professionals. For one thing, you may need someone with a fire operating permit to get the job done, since it involves working with an open flame. Also, a botched installation job can result in water getting stuck between the layers while rolling out the roofing.

It’s important to note that many liability insurance companies don’t cover torch down applications. If you hire a contractor for this job, you should ask for a letter from their insurance carrier confirming that they have coverage for this type of work. 

Contact a roofing professional near you for a consultation and a quote.

What Is the Cost of Torch Down Roofing?

The cost of torch down roofing is typically between $7,000 and $14,000. Considering that the average cost to install a new roof on a home with an angled roof is about $25,000, you're paying a lot less than a typical homeowner.

Labor will make up about 60% of the cost of installing torch down roofing. The roofing materials themselves will be about $1 to $3 per square foot, with labor running twice that. You may have to pay more if you live in a region where flatter roofs are common (such as arid climates), and therefore demand is greater for torch down roofing.

FAQs About Torch Down Roofing

How long do torch down roofs last?

Torch down roofs have a relatively short life span of about 15 years, although one with up to three layers may last as much as 20 years. One-ply systems generally come with a 12-year warranty and two-ply often comes with a 15 year warranty.

Is EPDM or TPO better than torch down?

EPDM, or ethylene propylene diene monomer, is an option for flat or low-slope roofs in northern climates. Thermoplastic Polyolefin (TPO) is similar, but better for southern regions. All three types have their pros and cons. EPDM typically is more durable than torch down roofs, whereas torch down roofs are better at reflecting sunlight. EPDM may also shrink more than torch down roofs, which can result in problems with the roof. TPO and EPDM are both better for handling ponding water, so they’re ideal for perfectly flat roofs.

Can you walk on torch down roofing?

Yes, you can walk on torch down roofing. It is durable and tear-resistant enough to handle that kind of low-level wear.

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