5 key problems with spray foam insulation and how to solve them

• Getting spray foam insulation presents problems for homeowners
• It can damage roofs, the environment, and impact health
• While an effective insulator, it might be better to get a less damaging alternative
• Spray foam insulation can last up to 80 years with the right maintenance

Spray foam insulation is an effective way to keep your home warm, but it’s not without problems. It’s not particularly environmentally friendly, for example, and it can make your home difficult to remortgage (if not impossible).

We’ve looked into the 5 key problems with spray foam insulation and more importantly, how to solve them.

If you’re all ready to get spray foam insulation, just fill in this simple form to start. All you need to do is put in a few details about your home – we’ll put you in touch with our trusted suppliers and they’ll get back to you with obligation-free quotes for you to compare.

It’s not eco-friendly

Even though spray foam insulation helps homes stop wasting energy (in turn, helping the environment), you can’t escape the fact that the majority of spray foam material insulation is just not eco-friendly.

In fact, it’s overwhelmingly made from materials that are not sustainable, so in the long run it’s difficult to see it as the catchall solution for insulating our homes.

Spray foam insulation is a petroleum-based product too, and as the world moves away from fossil fuels, spray foam insulation will inevitably become a thing of the past.

It isn’t just what spray foam is made from either – applying it has big environmental risks that are hard to ignore.

When you apply spray foam, you need to use a ‘blowing agent’These are commonly made from a mixture of hydrofluorocarbons and therein lies the problem.

Basically, hydrofluorocarbons have an incredibly high ‘Global Warming Potential’ (GWP). GWP is measured from a base level of 1, with carbon dioxide (CO2) from burning fuel defined as the start of the scale.

Methane (CH4) is well-known as being a good deal worse for the atmosphere than carbon dioxide and has a GWP level of 28. This makes it 28 times worse for the environment than carbon dioxide.

How bad are hydrofluorocarbons then? Really, really bad – hydrofluorocarbons have an astonishingly high GWP level of 3,400, which would make releasing just 1 kilogram of the stuff into the atmosphere the equivalent of releasing 3.4 tonnes of carbon dioxide.

Some types of spray foam insulation also contain volatile organic compounds (VOCs). These VOCs can be harmful not only to the environment, but to human health.

From a recycling point of view, spray foam insulation is pretty dreadful because of how it clings to roofing materials. This makes recycling any parts of your roof (for example during renovation or even a full roof replacement) very difficult.

How to fix

Spray foam insulation might be good at keeping heat in and stopping energy wastage. But you can’t escape from the fact that most spray foam is made from unsustainable materials.

You could opt for a more environmentally friendly insulation, such as cellulose insulation. This alternative is made from recycled paper and other plant-based fibres, making it biodegradable, unlike spray foam insulation.

Another alternative to ordinary spray foam insulation, called Icynene, is promoted as a much greener option. It’s made from recycled materials and doesn’t contain any harmful gases, toxic chemicals, or synthetic blowing agents.

Most spray foams are applied using a toxic blend of highly damaging chemicals, but Icynene is applied using a 100% water-blown solution. This makes it a more eco-friendly approach to spray foam insulation.

Spray foam insulation can cause roof damage

Like other types of insulation, spray foam insulation can be installed in the attic or roof, as well as under the floors, or in the walls.

Spray foam insulation, when done correctly, shouldn’t cause any significant damage to your roof. However, if you’ve opted for what’s called “closed-cell” spray foam in your roof, you do run certain risks.

Closed-cell foam is less porous than open-cell spray foam. What this means is that the warmth will have nowhere to go once it dissipates into your loft. This might not sound like a problem, but the greater warmth has a hidden danger – expansion and contraction.

When things heat up, they expand and subsequently, when they cool down the contract. It is this process of expansion and contraction that can cause damage to roofs.

Expansion and contraction causes gaps to appear in key parts of your roof, which decreases their structural integrity.

After a while of this process happening again and again, the likelihood of damage occurring increases.

Additionally, spray foam insulation can increase condensation in the winter, which can cause damage to untreated timbers. Damage to timbers can directly impact the structural integrity of your roof.

Spray foam insulation is really the only type of insulation that can cause significant roof damage. This is because most types of insulation don’t ‘stick’ to your roof the way spray foam does. For example, you can easily remove fibreglass insulation if you want to, but spray foam insulation removal is a difficult and potentially damaging process.

The potential for damaging roofs is one of the reasons spray foam insulation can make your home difficult to mortgage (or remortgage).

It’s worth noting though that not all mortgage companies dislike spray foam insulation. It’s just that some mortgage companies are unsure about remortgaging homes with spray foam insulation because of the risks it can pose to the structural integrity of the roof.

How to fix

You can avoid this by opting for open-cell spray foam insulation, but as this type of insulation is not water resistant, any leakage from your roof could turn it into mush.

Alternatively, you might consider ventilation options such as a window (a roof window like a Velux is ideal for this), or a roof vent. The downside is that these add to the overall cost, but when you think about it, a new roof would be a lot more expensive overall!

On average, a single Velux window costs between £305 and £1,800, depending on the size of the window and location.

Be sure to maintain you spray foam insulation every once in a while too. Proper maintenance for spray foam installed in the roof includes regular yearly inspections to fix any holes or cracks.

Lastly, it’s best to avoid applying spray foam insulation near electrical outlets or recessed lights (the type that are embedded in the ceiling) – if the foam expands, it can damage the electrical wires.

Wondering whether spray foam is worth the hassle? Check out our page Is Spray Foam Insulation Worth It? to find out.

It can cause health complications

Spray foam insulation is known to potentially cause a few health issues, including:

• Asthma
• Sensitisation
• Lung damage
• Other respiratory and breathing problems

There are chemicals found with some spray foam types that contain carcinogenic properties (such as benzene), which can increase the chances of developing cancer. Some also contain toluene, which has been linked to neurological damage, and xylene, a substance that can irritate skin and eyes.

Additionally, the emissions released when applying spray foam can be damaging. We mentioned VOCs earlier, which react with chemicals in the air to form potentially dangerous compounds such as nitrogen dioxide.

This can lead to headaches and eye irritation if absorbed by someone over a long-enough period.

How to fix

A lot of the potential health problems comes from the excess gas left behind after installing the spray foam insulation. Homes will typically have to be evacuated for a minimum of 24 hours after installing spray foam insulation.

If the process isn’t done properly, the gas can continue to cause issues for a while afterwards, increasing the risk of the health complications above.

Spray foam insulation can cause bad smells

There’s a pretty unfortunate problem associated with spray foam insulation – bad smells, or more specifically, a fishy odour that seems to hang around for months after installation.

Whilst definitely unpleasant, the issue is thankfully rare.

For those unlucky enough to suffer from this, the cause is usually the fault of the installer. If they’ve applied the spray foam either too thickly, or too quickly, the reaction that causes the spray foam to expand properly is interrupted.

Applying it too quickly makes the exothermic reaction get too hot, meaning the next layer doesn’t react properly. When you apply it too thickly, the layer underneath cannot expand as it normally would, leaving gaps and causing the spray foam to again react incorrectly.

When the foam reacts in the wrong way, it gives off excess gas, which causes the nasty smell. Another reason for this is where the installer doesn’t use the correct mixture of chemicals.

This doesn’t automatically mean the installer is at fault, because oftentimes they just work with the chemical mix they’re given.

How to fix

The key way to avoid this issue in the first place is to make sure you get a reliable, professional, and well-regarded installer, one who knows how to install spray foam insulation properly.

If you’re already dealing with the issue, fixing it is challenging to say the least. You can’t simply ‘fix’ a bad chemical reaction without either removing the spray foam insulation entirely, or waiting for the problem to fix itself.

The latter is almost always a bad idea, because the sheer volume of material used in spray foam insulation means that the gases giving off the odour will linger for months (and in some really bad cases, years).

Removing the spray foam is also incredibly difficult, because of how effectively it clings to surfaces.

Other options include contacting the spray foam manufacturer, where normally you should be able to send a test sample of the insulation. They’ll see if they can determine the cause, but again, it’s not going to actually fix the problem.

Also, if you have your HVAC (heating, ventilation, and air conditioning) in your loft, there’s a chance that the ducts are leaking. This might lead to the bad smell being circulated around your home (again, the smell is still there, so even this isn’t a fantastic solution to the issue).

Mould and mildew is (sometimes) a problem

When you use closed-cell spray foam, you get a much tighter insulating seal, which keeps a lot more heat in than other forms of insulation.

The major potential downside of this is that, by keeping in so much warmth, you can create the perfect environment for mould and mildew to flourish.

Of course, mould and mildew is not a given with spray foam insulation – in fact it’s actually more likely for both mould and mildew to appear with fibreglass and fabric insulation.

One thing to note is that there is a conflict of interest between businesses promoting spray foam insulation, and businesses promoting alternatives.

The former insist that spray foam insulation is great for preventing mould and mildew, and the latter usually stress the opposite.

How to fix

Fixing mould and mildew is a case of trying out one of the many, many different recipes available online (bleach and water solutions are a popular option, or undiluted white vinegar if you prefer a more eco-friendly approach). Your best bet however, is preventing it from occurring in the first place.

For starters you should make sure when you get spray foam insulation, you don’t spray over surfaces that are showing the telltale signs of mould and mildew.

Both actually only take between 24–48 hours to appear, but at this point the growths can be small enough to miss entirely. So you should first assess your loft for any problem spots before committing to insulating it with spray foam.

Alternatively, if you use open-cell insulation, your roof will be able to ‘breathe’ more effectively.

Next steps

While spray foam insulation is effective at keeping your home warm, the problems listed above make it difficult to recommend fully. Your best bet is to consider other forms of insulation, particularly environmentally friendly alternatives such as cellulose insulation.

You can get an idea of which insulation will be best for your home by filling in our simple webform. All you need to do is enter a few short details about your home, and we’ll connect with our expert installers.

They’ll get back to you with obligation-free quotes for you to compare.