Where & When Not To Use Expanding Spray Foam Insulation

Spray foam insulation is a boon for homeowners trying to fix loopholes in their house. Right from doors to windows, they are the product to go for. They also come in cans that are not only cheap & effective but are potential energy savers as well. They play a good role in summer and in winters too. But, one needs to make sure where & when not to use expanding spray foam insulation.

WHERE Not To Use Expanding Foam

Here we’ll look into areas where spray foam insulation should never be used.

Around Electrical Outlets

Spray foam should never be used in and around electrical boxes. This is a widely done practice homeowners use insulation around electrical outlets.

But if by any chance, the spray foam gets inside these boxes the chemicals in them are highly exposed to electrical sparks. This chemical is highly flammable and can cause fire easily.

Furthermore expanding foam should never be used in and around electrical boxes.

Around Your Cooking Area

Since spray foam has flammable chemicals in it, it’s better advised not to use it anywhere close to your cooking area.

By cooking area, we mean any place that is close to your cooking stove.

Around Wires

Using SPF around wires can be tricky as it can damage the surrounding electrical wiring. When filling gaps be careful not to overfill a cavity.

Naked wires should never come in contact with spray foam as they can act as an insulator. This can increase the temperature of the wires. Heat in the wires as a result will not be able to escape which can cause overheating and can be a leading cause of a fire.

On The Roof

Now a lot of you may disagree, but we’ll make it clear. Under expert supervision and with a team of experts this can be safely executed. Spray foam applications on roofs are done for ages but can be done properly only in the presence of experts.

Why shouldn’t you do it on your own and what problems can it cause? We’ll find out below.

When you apply spray foam on the roof, problems will arise during rainy weather. The reason being that the water gets trapped in some gaps. This trapped water can speed up the decomposition process and can spoil your roof.

If you live in a high humidity area the foam will allow moisture to get sucked and that can cause some problems too.

Plywoods on roofs with their surface evened out are also vulnerable. The reason being that water can still get trapped & absorbed on plywood edges. This will decrease the shelf life of your plywood whilst making sure you need to change them sooner than expected.

Moreover, wind can cause a lot of over spraying problems as well. Air can carry the foam to the surrounding property and can cause issues.

Roofs repaired with spray foam needs to have maintenance checks at least twice a year. When you detect any leaks or cracks, then that must be fixed with a sealant to make sure your roof remains intact.

SPF roofs have a low resistance to outside air & weather conditions. So be prepared to spend some money once or twice a year for repairs. This is one of the main reasons why homeowners are hesitant to go with this option.

WHERE Not To Use Expanding Foam

Here we’ll discuss when you should avoid using spray foam insulation.

Never Use Expired Spray Foam

Using expired spray foam is something you should never do. There are a lot of material & density problems that can occur in such usage. The material shrinks and the foam you get on an application will shrink as well.

The foam density often increases when using an expired product. Homeowners might think they’re getting their bang for the buck. But in reality, the yield decreases due to increased foam density.

Spray foam materials work on fast reaction, the faster they work the better they can hold shape. This ability decreases in a product that has gone beyond its shelf life.

Tip – Never use a spray foam too close to the expiration date as the chemical imbalance increases as time goes by.

In Case Of Allergies

Spray foam insulation does come with some health concerns & risks. People who are allergic to these should stay clear from them. Some people may even react negatively when they are in close proximity to spray foam.

Problems ranging from gastrointestinal issues to eye infection and sometimes even skin problems are reported in some. Yet, it doesn’t majorly affect a lot of people but the sensitive ones should make sure to try another alternative.

Even if you’re not allergic to them or don’t have an underlying health issue, it is still advisable to wear protective wear at all costs when using these.

Your protective gear will consist of goggles to protect your eyes & a respirator to make sure you don’t inhale it.

If You Care About The Environment

Spray foam insulation has been criticized a lot for not being environment friendly. In recent years a lot of talks have been made about the importance of carbon footprints and how we can reduce them.

SPF though has come out as a villain as far as the carbon footprint is concerned. They contain chemicals that are high in GWP (Global Warming Potential). This makes it a lot of times worse than the impact caused by Carbon Dioxide.

However, there are closed-cell spray foams that are low in GWP and adequate research must be made before buying them. In recent years products have come out with low GWP which results in minimum damage to the ozone layer & the environment.

But this issue largely remains with the use of the majority of spray foam insulation products used in any form.


We have touched on areas as well as times where the use of spray foam should be limited. Even though with some tweaks there are areas where you can use them and there are instances when they are a better alternative to others.

At all times though, all factors must be taken into account. And when needed call an expert to do the job for you.