Is Spray Foam Insulation Flammable? Types, Safety Measures, And More! 

Are you getting a new house or renovating the old one with Spray foam insulation? Well, congratulations in both cases! However, have you considered the flammable property of these insulations?

To begin with, is spray foam insulation flammable?

Unfortunately, despite being treated with fire retardants, it still somehow remains flammable and can catch fire when it reaches 700 degrees F temperature. Besides, it can also ignite when exposed to a heat source.

But don’t worry, that shouldn’t scare you if only you understand Spray foam insulation better and keep in mind the possible fire risks that come with it. Also, we are going to give you some safety measures to follow up on. That should be enough, so let’s get in!

Is Spray Foam Insulation Flammable

Understanding Open-cell and Closed-cell

Nonetheless, spray foam has turned out to be quite popular in recent days for both residential and commercial purposes. However, it’s important to know the types of spray foam insulation before you can apply it in your homes. 

If you didn’t know, there are two types of spray foam insulations, open-cell, and closed-cell. While the terms might sound confusing at first, as we discuss them in detail, you’ll be able to understand them easily. 

To begin with, the differences in the spray foam insulation come from the differences between the bubbles or cells that make the foam into a whole.

Open-cell Foam

This type of spray foam insulation is composed of a less thick, supple foam compared to closed-cell insulation. Since the cells in this type of foam are not entirely closed, air can easily move through the material. Having a lower R-value than closed-cell insulation, it is comparatively less effective in insulating against heat transfer.

Open-cell Foam Insulation Benefits

1. It is a more cost-effective option if you are under a budget constraint.

2. Open-cell foam stands as a better option for soundproofing since it has better sound-absorbing qualities.
3. If mold growth is an issue with your home, open-cell insulation aids better in moisture control. 

Open-cell Foam Insulation Drawbacks

1. With a lower R-value than closed-cell insulation, open-cell spray foam shows less productivity in heat transfer insulation.

2. Since it has low density, the foam is not able to provide a strong and efficient barrier compared to closed-cell insulation

3. With low density and a more porous structure, it has greater permeability to air and moisture, making it more flammable. 


Open-cell spray foam is mostly used in residents, especially in crawl spaces, attics, or smaller places that show chances of leaking cool and warm air.  

Besides, since it is better at sound absorbance, it is sometimes used for commercial purposes, especially in theaters. 

Closed-cell Foam

Closed-cell spray foam insulation comes with a more packed and solid structure and naturally with a higher R-value (thermal resistance rating) than open-cell foam insulation. 

Since the cells in the spray foam are mostly closed, oxygen cannot typically pass through the materials. As a result, closed-cell spray foam insulation shows more effectiveness in resisting heat transmission.

Closed-cell Foam Insulation Benefits

1. Being compact within its structure, closed-cell insulation shows more resistance to moisture, helping to prevent mold growth within it.

2. The dense foam construction offers a more rigid, strong, and solid barrier than open-cell insulation. 

3. As mentioned, it has a greater R-value or thermal resistance rating compared to the open-cell one and hence is better at insulation.

4. With less space for air and oxygen to pass through, closed-cell foam is comparatively less flammable than open-cell foam.

Closed-cell Foam Insulation Drawbacks

1. Undoubtedly, if you want more insulation and solid construction, you’ll have to pay more, which makes the closed-cell foam more expensive.

2. With more rigidity comes less flexibility, making it unsuited for all 


3. For proper installation of this type of foam, you need more skills and even professional assistance. 


Closed-cell foam usage is more prominent in newly constructed buildings or renovated ones since they offer better support to the structure. 

Besides, they are also used in many commercial buildings, particular regions in a house, such as roofs or attics, and even big camper vans. 

Why Is Spray Foam Insulation Flammable?

Undoubtedly, spray foam insulation application is increasing every day thanks to its fantastic thermal performance and leak-sealing properties. However, the material being flammable raises second thoughts in users. 

So, before we dive into the safety measure, why don’t we take a look at the properties of spray foam insulation that make it flammable? 

High Carbon and Hydrogen Chemical Composition

To understand why spray foam is flammable, we have to get inside it. So, what makes up spray foam insulation? Chemicals with a high carbon and hydrogen content, which includes polyol resin and isocyanate, are used to make spray foam insulation. 

These core elements are highly flammable and can catch fire when exposed to heat or flames. And hence, this chemical makeup is the first and foremost reason why spray foam insulation is highly flammable. 

Application of Blowing Agents

To build the structure of the spray foam insulation, many times, blowing agents are used. These blowing agents include hydrocarbons and fluorocarbons that can increase the overall flammability of the insulation. 

The concerning part is that even if the foam insulation is not flammable itself, the addition of these blowing agents can increase the risk to a greater extent. 

Mixture of Chemicals

Do you know how spray foam insulation is created? It involves mixing two or more chemicals, typically polyurethane and isocyanate. This later produces extreme heat and releases flammable gas products as well. 

Since it generates a good load of heat while forming its structure, it naturally raises the risk of fire; besides, if it is not mixed properly or given an excessive amount of time to cure, the risk of flammability levels up.  

Addition of Accelerants

To hasten the curing process, occasionally, manufacturers may add accelerants to spray foam insulation products. Now, these accelerants many times may cause the insulation to become more flammable and prone to catching fire.

Apart from that, some accelerants can also produce heat, further increasing the possibility of fire during installation. 

Problematic installation 

Finally, this is the part where many people do not pay enough attention. When spray foam insulation is not installed properly, there is a high risk that there are open crevices and gaps. More gaps increase the risk of combustible gasses building up and starting a fire. 

Apart from that, there’s always the risk of the insulation tending to catch fire if it is too close to any heat source. This can be a heating stove, oven, electric outlet, or simply a light fixture. 

So, what you need to do to tackle this situation is employ appropriate installation methods and make sure there is sufficient ventilation. The rest of the safety measures you’ll know in a minute!

Is Spray Foam Insulation Explosive?

As mentioned, the two main components used to make up spray foam insulation are isocyanate and polyol resin. They are combined following a chemical reaction which eventually creates an expanding foam. 

Although the spray foam insulation is generally treated with fire-resistant in a decent amount, however, it remains somewhat flammable or even explosive under certain conditions. 

Ignition point

You already know that spray foam is considered a combustible material, but at what temperature does it combust? To put it simply, what is its flash point? When it leads to an extreme temperature of 700 degrees C, it will tend to ignite. 

Highly flammable propellants

Besides, don’t forget that as you apply it, the spray foam will immediately emit propellant gas. These gaseous elements are used to help pass out the foam as it slowly expands and gradually dries out. 

But there is a catch: these propellant gasses are highly flammable, and if, unfortunately, there is an ignition source nearby, it might even cause an explosion. 

Increase in pressure

So, that’s an idea of how spray foam can be explosive when it is applied. But is that it? No! Lack of maintenance of the spray foam equipment can lead to damage or even breakdown, eventually leading to a pressure buildup. 

Due to this pressure build-up, it’s common that the equipment will rupture, and finally, an explosion will arise from it.

Storage mismanagement 

Lastly, there’s another potential risk of explosion of the spray foam insulation when it comes to inappropriate handling, disposal, or storage of the chemicals used. Since the chemicals are highly flammable, in case if you don’t properly store or dispose of them, they will burn or even explode following certain conditions. 

Of course, none of us wants to be put in any of these situations. But even if it happens, how do you put off a fire led by Spray foam insulation?

How to Put Off a Spray Foam Insulation Fire

No matter what the source is, catching fire is always a terrible thing to happen. So, If spray foam insulation catches fire, what should you do? Take a deep breath and follow the steps mentioned below.

Step 1: Evacuation for Safety

This is the basic first step when there is a fire; simply evacuate the area at once! If there’s an alarm, use it to alert everyone aware or unaware of the situation to get out and then call the emergency numbers.

Step 2: Cut Off the Power

Due to a power connection or the electrical outlets and devices around the fire, there is a possibility that the fire might spread out. So, if possible, try to turn off any power source in the affected area, including all the electric devices. 

Step 3: Get the Fire Extinguisher!

Before you jump into extinguishing the fire, you need to assess the situation, size, and how serious the fire is. If the fire is only covering a small area, a few people may easily put it out with a fire extinguisher. 

However, the scary part is when the fire has engulfed a large area. In this case, you don’t need to be a hero by trying to handle it yourself. Simply evacuate the area and call for help. 

Step 4: Halt Oxygen Supply

Anything, including fire from spray foam insulation, required oxygen to keep burning. So, what you need to do is calm down and cut off all the oxygen supply to the affected area. And the easiest way is to close all the openings.

Of course, this will not put the fire out; however, it will surely prevent the spreading. 

Step 5: Use Water or a Fire Blanket

If you cannot find the fire extinguisher, it’s not working, or if the fire is too large to be handled by the fire extinguisher, your best option is water. Get a few buckets of water, and better if you have a water hose nearby to extinguish the flames.

In case of smaller fires, you may try using a fire blanket to smother the flames. Grab the blanket, put it over the flames, and leave it there till the fire is out. 

Step 6: Reach Out to the Fire Department Immediately

Whether you can or cannot handle the fire alone, you need to reach out to the fire department to handle the situation better and find out if there are still potential fire hazards hovering.

Spray Foam Insulation Safety Measures

To make sure a fire incident doesn’t start from installing spray foam insulation, take the following safety measures. 

Work with Protective Clothing and Accessories

The first and foremost step for preventing any fire mishap is to wear protective clothing as you work with spray foam insulation. And the perfect dress-up code for this work is long-sleeved fireproof suits or clothes, long trousers, safety glasses, and fire-proof gloves, of course. 

Proper Ventilation Is a Must!

Before you start with the installation, make sure the area of the application has proper ventilation. To ensure you have a total circulation of fresh air, turn on the fan, and open all windows and doors.

Pay Attention to Manufacturer Guidelines

Remember this when applying spray foam insulation or using any equipment, follow the instructions from the manufacturer. Not only does this include proper usage of the equipment but also correct mixing ratio, maintaining the drying time and temperature. 

Follow Building Codes for Fire Safety

To guarantee fire safety, you mustn’t neglect the local building codes. Besides, you should only rely on certified and qualified professionals for the installation of foam insulation. Otherwise, there’s every possibility that there can be a fire incident, and you don’t want it!

Check Electric Wiring Before Installation 

Checking out the proper placement and condition of electrical wiring both before and after the installation of spray foam insulation is another precaution you must follow ahead.

 If you don’t know, faulty or damaged wires can spark and start up a fire when in contact with an ignition source. Also, don’t forget routine maintenance of the wiring to make sure everything is okay.

Better to Use Fire Retardant Spray Foam 

Do you know what’s the best thing to do beforehand? Simply choose a fire-retardant spray foam insulation product, to begin with! These products have fire-retardant chemicals used on them that can slow the spread of fire for up to 30 minutes!

This offers more time for the occupants in the fire hazard zone to safely evacuate from the area. 

Don’t Forget Fire Barriers

When you are installing spray foam insulation, most building standards, including IRC or International Residential Code, mandate that you cover it with a 15-minute thermal barrier. 

If you are applying the foam in an attic or small space, you can simply use an ignition barrier as well. Surprisingly, this can reduce the risk of fire incidents by 50%! So, why not?

Store and Dispose of Properly

And lastly, don’t just throw it off at some corner after using the spray foam insulation. Store it carefully in a cool and dry place away from any ignition source. And in case of disposal, follow the manufacturer or local building guidelines for flammable materials. 

Can Cinnamon Be Used as a Fire Starter?

Cinnamon can indeed be used as a fire starter. The oils in the bark are highly flammable and can catch fire easily, making it an effective natural alternative to traditional fire starters such as newspaper or kindling. So, next time you’re out camping, consider using a few cinnamon sticks to start your fire it might just save you some hassle.

Frequently Asked Questions

1. Is spray foam flammable after it dries?

Unfortunately, spray foam, even when it is cured and dried, remains flammable. It may even catch fire when exposed to high temperatures of 240 degrees F.

2. At what temperature does spray foam catch fire?

Despite being well treated with fire-retardant chemicals, even the Consumer Product Safety Commission or CPSC recognizes the material as a fire hazard. This material can catch fire at 700 degrees F.

3. How long after the spray foam is safe?

As per EPA guidelines, the occupants need to stay away from the area where the spray foam insulation is being installed for up to 1-3 days. However, in case the spray foam keeps releasing gas, the time duration can multiply. 

Wrapping Up!

To finish off, yes, there’s no doubt that spray foam insulation is flammable. But the question is, can you go without it? Of course, you can’t because it has shown amazing insulation and leak-covering abilities. So, your best course of action is to understand how it works and take safety measures accordingly when installing it.

Here’s some advice, although a bit expensive, there are fire-retardant spray foam insulations available in the market. Try getting these to lower fire risks, and no matter what, follow the application instructions just to be on the safe side. That’s all for today; stay safe, folks!