A Welder in the Office

A Welder in the Office

Spray Foam Insulation: Thermal Barrier Vs. Ignition Barrier

Gregory Walker

Insulating your home with spray foam insulation can help you save up to 50% on future utility bills. Although spray foam insulation has been praised for its ease of installation and its high R-value, all types of spray foam insulation are flammable, and require either an ignition barrier or a thermal barrier to be installed alongside. 

Fire Hazard of Spray Foam Insulation

Spray foam insulation is especially hazardous if it is exposed to a fire source. Unprotected spray foam insulation can easily ignite. It is crucial that the spray foam insulation was installed to code. Depending on where the spray foam insulation is installed, it will either require a thermal barrier or an ignition barrier; however, the regulations surrounding the requirements can be hard to decipher at times. Your best bet is to consult with a contractor with a lot of experience in installing spray foam insulation.

Differences Between Thermal Barrier vs. Ignition Barrier

A thermal barrier is considered as more secure than an ignition barrier. The requirements regarding the installation of a thermal barrier is found in Section R316.4 of the 2009 International Residential Code (IRC). According to this regulation, the spray foam insulation needs to be separated by an approved thermal barrier that has a minimum thickness of 1/2 inch. Most contractors will use drywall although there are other materials that have been approved. A thermal barrier is required most of the time, and is responsible for stopping the fire from entering the living space. 

An ignition barrier is less stringent and offers less protection in comparison to thermal barriers. Ignition barriers can be installed in foam-insulated attics, crawlspaces and other spaces that cannot be used as a living space. One easy way to determine whether you need to install a thermal barrier or an ignition barrier is to take a look at the door that accesses the area. Ignition barriers can be installed in spaces where access to the space is through a hatch door.


You want to make sure that you are fully aware of whether a thermal barrier or an ignition barrier is needed, as it can make a huge difference to the safety of your family. There are many different types of materials that you can choose from. Generally speaking, closed spray foam insulation is harder to ignite than open foam insulation. You may want to take this into account when considering the type of spray foam insulation that is best for your home. Contact an outlet, such as Bios Environments, for further assistance.


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About Me
A Welder in the Office

Hi, I'm Caroline. Welding has always been really fascinating to me. One day, when I was at work in my office, we had a leaky pipe in the ceiling. After calling a plumber, he called a welder who came to repair the large, open pipe. As we were all sitting there trying to work, the welder just came in and started repairing the pipe! I had never worked on a construction site before, and I probably never will. But I started thinking about what it would actually be like to work on a construction site, which led to me exploring construction themes and writing this blog!