how to install torch down roofing - roof master

How To Apply Torch Down Roofing: Full Guide

When you are planning a commercial project, there are several things you should consider. But, one of the most critical elements is the roofing material you will use. In this case, for a flat or low sloped surface, you might be thinking that EPDM is the best option. However, before taking the final decision, you should look into torch-down roofing. 

Torch-down roofing is one of the most popular choices when it comes to any commercial or industrial buildings. This material offers several benefits, such as a watertight seal and protection against UV rays. However, this is not a roof that works for everybody. That’s why you should keep reading to find out if this is the perfect option for you.

In the end, if you decide this is the material you want to purchase, we will tell you how to install torch-down roofing. 

What is torch-down roofing?

The first thing you need to understand is that the name of the material comes from its installation process. A torch-down roof requires multiple layers of modified bitumen. This product has two parts, a polyester mat and a membrane located within an asphalt layer. 

The torch-down roofing is available in two types of sheets, smooth and granulated. The good thing about choosing smooth ones is that you can use them in case you need new roofing in the future. However, if you need a roofing replacement with the granulated option, you’ll need to clean up the entire surface. But, on the other hand, this material will reflect sun rays which will reduce your energy bills. 

Overall, this material is durable and weighs only two pounds per square footage. This means you can install it by yourself, which will save you a lot of money. 

Types of torch-down system

As we mentioned above, this kind of roofing consists of several layers. That’s why, depending on the system you choose, you will have a two or three-layer torch-down structure.


A two-layer torch-down system is easy to install, and it is affordable. However, the only downside is that it won’t last as long as a three-layer one. This structure will be made of a base layer and a cap sheet. 


As you might have guessed by now, if you choose a three-layer torch-down system, the price will be higher, and its installation will take longer. But, on the bright side, you will get more protection and benefits. The only difference between this roof and the one above is that the cap sheet used during this process will be granulated. 

Torch-down roofing lifespan

For a two-layer torch-down, the expected lifespan will be 15 years. However, if it is a three-layer torch-down roof, it will last up to 20 years. What will help you decide which roof is better for you is your budget? Keep in mind that with proper maintenance, you can expand the life expectancy of your torch roof. 

How to install torch-down roofing

Whether you plan to do it on your own or hire a team of professionals to install it, it is important to understand how to apply torch-down roofing. However, there is no need to worry. You can do this in six easy steps that we will explain below. But, before we jump into this process, let’s look at the materials we will need and the necessary preparation.


If you are going to do this on your own, you need to be careful. Remember that the number one priority is your safety. Before you get started, here are some tools you should gather. First, to protect yourself, purchase gloves, boots, and a helmet. Then, look for a hammer, drill, ruler, cutter, spark igniter, and bitumen primer. The last step will be getting your torch-down roof. If you don’t know which exact measurement to get, you can ask somebody in the hardware store. 


When most people ask, “how to do a torch-down roofing installation?” They never think about preparation, which is equally important. First, you need to make sure that your surface is free of any kind of debris. To complete this process, you can use a leaf blower. Don’t forget to be careful because while you are on top of the roof, some areas might be unstable. If you previously had another material on top, then you need to remove it before starting. 

Step-by-step installation

In this section, we will tell you how to apply torch-down roofing step-by-step. Here is where you can’t cut corners; otherwise, your roof will end up being unstable and could get damaged more easily. 

1) Applying insulation

Insulation is a necessary element for all flat roofs, especially in cold weather. You can attach this element to your roof using glue or screws. However, that will depend on your surface. Remember that will be the base of your roof, which means it needs to be perfect.

2) Take care of the moisture barrier

The moisture barrier is the only element that will prevent condensation and water damage. This is a crucial step you can’t skip since it will expand the lifespan of your roofing system.

4) Overlay board

The overlay board needs to be carefully installed since it will be the support surface of the torch-down membranes. If you are not successful, then you won’t have a leveled roof. Plus, there is a high chance that the structure could suffer water damage. 

5) Installing base sheet

This is the first layer of your roof, and you will attach it to the overlay board. You can perform this process using adhesive, but some professionals also like the heat fusing method. 

6) Applying cap sheet

To install this second layer of the material, you will need a torch. As you roll out this cap sheet over the base, you will heat the underside. That way, the base, and the cap will fuse, which will form the watertight seal. If you chose a three-layer torch-down roof, the contractor would have to install a third granulated surface following the same steps.

7) Applying flashing

Now you just have to apply flashing to prevent any leaks, and then you are done.

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