Is Spray Foam Insulation Safe?

Kenneth Wilson

It’s evident that spray foam is heavily used within the US construction industry. This is because it’s a primary go-to option for home renovations due to its simplicity of installation. However, spray foam has had some controversial discussions about its safety as it contains harmful chemicals. So, is spray foam insulation safe?  

When properly installed, spray foam insulation is entirely safe for every property type. The dangers based around this installation only occur if the foam isn’t cured before the property becomes re-inhabited. 

The danger behind spray foam insulation only happens when applying it. This is why it’s essential to get a licensed insulation contractor to use this type of insulation on a property. Hiring someone who specializes in this insulation will ensure they’re following chartered safety measurements when installing. 

What Makes Spray Foam Insulation Unsafe? 

As we’re now aware, when installed correctly, spray foam is entirely safe. The risk that comes with this foam is actually the curing aspect, which is why installers need to wear the appropriate protective equipment when handling the insulation. 

The chemical that makes this application dangerous is isocyanate, which is formed from diisocyanate, methylene diphenyl, or MDI. If you become exposed to this chemical for a prolonged time, it can develop liver problems, kidney disease, lung damage, and even cancer. 

Therefore, it’s essential to hire a licensed professional and not to undergo the job yourself. When applying this type of insulation, more in-depth knowledge is required to ensure both you and your property are safe. 

While hiring a professional to install spray foam insulation, they’ll first start with inspecting your property. This includes the structural integrity, ventilation systems, and layout to ensure this type of insulation is best suited for your property type. If required, they’ll then take accurate measurements and calculate how much spray foam insulation you need. 

If they go ahead with the job, the occupants will be asked to leave until the spray foam insulation has cured. This could be anywhere between 8 to 24 hours, but it really depends on a bunch of environmental factors like temperature, humidity, etc. 

Advantages and Disadvantages of Spray Foam Insulation 

From reading the above, you can quickly understand why there’s so much controversy around this insulation. Apart from being harmful when applying, it’s still widely used within the construction industry for one primary reason - that’s because it’s good. But what are the advantages and disadvantages of using spray foam for insulation? 


First, let’s start with the advantages. If you’re someone considering spray foam, I recommend you become familiar with the below before making your final decision. 

1. Can Be Considered “Airtight” 

The number one reason why spray foam insulation is such a popular insulation choice is because of its expansive nature. When foam insulation is applied, it expands 2x, 4x, and maybe even 5x its original state. While it expands, it also works its way into micro air pockets, allowing for maximum insulation. 

2. It’s Incredibly Durable

Including the above, spray foam insulation is very durable and difficult to break. Because the product expands into various cracks, holes, and hairline crevices, it creates an air-tight material that isn’t subjected to water or air movement. 

3. Spray Foam Has Superb Longevity 

Compared to other insulation methods, spray foam has a much longer lifespan. With this insulation, you can reek the benefits from it for decades to come without even having to think about replacing it. Although the installation cost is much higher than other insulation methods, it may be worth considering due to its longevity. 

4. It’s Somewhat Eco-friendly 

Although there are chemicals found within the foam, the energy consumption and protection benefits it offers makes this more eco-friendlier than what meets the eye. It’s also made from fewer products considering the yield you can get from a single can, and this is due to its expansion capabilities. 


Like with all advantages come disadvantages. Although many of the below can be avoided by using a professional installer, it’s more than worth becoming familiar with them.  

1. Spray Foam Isn’t 100% Accurate

Although we’ve spoken about the foam expansion seeping its way into small holes and cracks, sometimes it isn’t 100% accurate. This depends on how the foam is laid and how it expands onto a given area. 

2. It Can Sometimes Shrink

In many cases, spray foam is the preferred option because it’s quick and straightforward to install. However, one significant negative this has is that it can sometimes decrease in size. This is more prominent in geographic regions that experience extreme temperatures (hot or cold). If you encounter this, it reduces your insulation and the structural integrity of the property. 

3. Installation Is Expensive

When it comes to installation and material cost, spray foam is actually the most costly option. For example, to install fiberglass insulation, you can be expected to pay anywhere between $0.40 per square foot. In contrast, spray foam jumps to $1.50 per board foot (a board foot is measured to be 1x1 foot square with an inch of thickness). 

4. It Can be Hazardous

We mentioned this above, and that’s because spray foam can provide some serious health issues if it isn’t applied or cured correctly. The problems that can arise can be anywhere from skin rashes to respiratory problems. However, one way you can reduce this from becoming a problem is by hiring a professional to undergo the job. 

Alternative Insulation Materials

If you’re not interested in using spray foam for your insulation, there’s a boatload of different alternatives you’re able to opt-in for. You should consider: 

Mineral Wool

Sheep’s wool

Therma Cork


All of the above have their own unique pros and cons, but they’re still considered “good” insulation materials that you can implement in your property. 


After reading, you should now understand that spray foam insulation is entirely safe if applied and cured correctly. To avoid spray foam from causing health issues, you should hire a certified professional to tackle the job. 

If you’re budgeting and are considering applying it yourself, I don’t recommend it. It can cause more health issues than it’s worth, and it’s best to opt-in for other alternative materials such as mineral wool, sheep’s wool, Therma Cork, or even aerogel. 

So, now you understand the dangers and preventions of spray foam insulation, will you be implementing it on your property? 

Kenneth Wilson
August 22, 2021

Kenneth Wilson

Retired contractor. Currently residing in Southwest Florida. Now in semi-retirement, I write and manage this blog focused on helping home owners make savvy decisions when it comes to finding contractors and getting their projects done. I also operate remodeling design service for homeowners.

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