Common spray foam insulation problems (and what to do about it)

Is spray foam insulation installed in your home? You could be one of thousands of homeowners experiencing issues.

spray foam insulation

Spray foam insulation has been a popular choice for improving a home’s energy efficiency in the UK since the 1970s, with an estimated 250,000 UK homes having it installed. But recent reports have revealed serious problems that are leaving homeowners in a difficult position.

One legal firm alone reported having 700 open inquiries about compensation for spray foam insulation.1 And selling homes with spray foam insulation has become more difficult since many mortgage lenders have started refusing to lend on homes with spray foam insulation. Insurance companies are also denying building insurance for homes with spray foam insulation.2

In this article, we’ll look at the many problems associated with spray foam insulation, how these are leading to issues for thousands of homeowners across the UK, and what you can do about it.

What is spray foam insulation?  

Spray foam insulation is a liquid foam that can be sprayed in lofts, roofs, walls and under floors to insulate a home. The foam is blown from a spray gun and expands to fill an area and create a layer of insulation.

Unfortunately, spray foam insulation is usually made of unsustainable petroleum-based materials. More eco-friendly spray foams are available but even these aren’t ‘good’ for the environment.

There are two main types of spray foam insulation:

  • Open-cell spray foam: The foam bubbles are ‘open’ which makes them softer and spongier when set. This allows some moisture to pass through the foam but results in a lower insulation value (R-value) than closed-cell spray foam. Because it expands into gaps more than closed-cell spray foam, it’s often used to insulate hard-to-reach places or where soundproofing is needed.
  • Closed-cell spray foam: The foam bubbles are locked tightly together which makes them solid when they set. This prevents air and moisture from penetrating the foam layer, giving it a higher insulation value (R-value) than open-cell spray foam. Because it doesn’t expand as much as open-cell spray foam, it’s often used where space is limited.

Spray foam insulation has been used in the UK since the 1970s but has more recently come under criticism due to various concerns including potential health risks, structural issues and mortgage approval problems.

Spray foam insulation problems

While spray foam insulation can make a home more energy efficient, its downsides often out-weight its benefits.

If spray foam insulation isn’t installed correctly or is used in the wrong setting, it can cause all sorts of problems, from reducing ventilation to rotting wooden roof beams. This has caused many mortgage lenders to avoid lending on homes with spray foam insulation completely.

Thousands of homeowners have been left struggling due to problems with spray foam insulation. A couple in Stoke-on-Trent lost nearly £11,000 after having spray foam insulation installed because it rendered their home unsellable.3 Having already paid £4,926 for the installation, they then had to pay £5,490 to get it removed.

Here are some of the most common spray foam insulation problems:

  • Mortgage problems: Some mortgage lenders refuse to lend on homes with spray foam insulation as they consider them to have a higher risk of potential structural issues and loss of value. This can make it difficult to sell or get a mortgage for a home with spray foam insulation.
  • Insurance problems: Some insurance companies are refusing to insure homes that have spray foam insulation installed due to potential structural risks, such as trapped moisture leading to timber decay and roof damage.
  • Health issues: If not installed properly, spray foam insulation can release harmful chemicals such as isocyanates during and after the installation. This can potentially lead to serious health issues, from skin, eye and lung irritation to asthma and even cancer.
  • Environmental damage: As well as being made from unsustainable petroleum-based chemicals, most spray foams use blowing agents that contain hydrofluorocarbons (HFCs). These HFCs can emit greenhouse gases that are up to 1,030 times worse for the environment than carbon dioxide.4 Additionally, spray foam insulation isn't biodegradable or easily recycled and usually ends up in landfills.
  • Reduced ventilation: Because it’s particularly dense and fills all gaps, spray foam insulation can obstruct ventilation. This can trap moisture which can, in turn, lead to dampness, condensation and rotting roof timbers.
  • Home devaluation: The difficulty and high cost of removing spray foam insulation, along with the potential for it to cause unseen damage, can put off prospective buyers and negatively impact the home's value. And since mortgage lenders are often reluctant to lend on a property that has spray foam insulation, it can make it harder for interested buyers to fund the purchase.

What can you do if your home has spray foam insulation?

If your home has spray foam insulation installed, it’s not the end of the world - and it’s not necessarily all bad news. But there are several things you should consider.

  • Remove the spray foam insulation: Removing spray foam insulation can be difficult, messy and very expensive. In some cases, the roof may need to be replaced if the foam can’t be removed cleanly. Removing spray foam insulation should always be done by a professional, as the foam is often toxic. That said, if the foam is eco-friendly and has been installed correctly, it could be much easier to remove. So speak with an installer to find out.
  • Keep all the paperwork: By holding onto documents and emails that include things like product details, installer certifications, survey reports and guarantees can help you if you’re dealing with surveyors and mortgage lenders. However, it doesn’t guarantee they’ll be satisfied with the installation.
  • Consider a new mortgage lender: If you’re due to remortgage, you may find that your current lender no longer lends on homes with spray foam insulation. In this case, remember that there are still lenders out there who do. So consider switching to another lender rather than lapsing onto your existing lender’s expensive Standard Variable Rate.
  • Complain to the installer: If you or your home is suffering due to spray foam insulation, consider reviewing the terms of the purchase. If you find any issues, such as poor installation or failure to meet safety standards, you can submit a complaint to the installer. If you don’t receive a suitable response, you could escalate your complaint to the relevant accredited oversight body, such as TrustMark. Bear in mind that the installation industry is largely unregulated, and the installer may not be registered with any oversight body.
  • Claim compensation for spray foam insulation: If you believe you were misled about installing spray foam insulation, you can raise a dispute to claim compensation under the Consumer Protection from Unfair Trading Regulations 2008. Additionally, if you had the foam installed by a TrustMark-registered installer using the Green Homes Grant Scheme, you can follow TrustMark’s dispute resolution process.

Alternatives to spray foam insulation  

If you haven’t yet installed spray foam insulation, or you wish to replace existing spray foam insulation, you may want to consider the following options instead:

  • Fibreglass: Spun glass fibres that trap air, fibreglass is commonly used in lofts and walls. It’s affordable but could irritate your skin and lungs.
  • Cellulose: Made from recycled newspaper treated with fire retardant, cellulose is blown into cavities. It’s eco-friendly and a good insulator but can settle and become less effective over time.
  • Rock wool: Made from spun volcanic rock, rock wool is fire resistant and good for soundproofing. But it’s more expensive than other options.
  • Sheep’s wool: It’s a natural, renewable insulation that’s non-irritating and moisture-regulating. But again, it's a more expensive option.
  • Solid foam: Unlike spray foam, solid foam comes in pre-cut panels that can be fitted into place. It’s often made from polyisocyanurate (PIR) or extruded polystyrene (XPS) which are good insulators. But it can be harder to insulate corners and irregular gaps due to its rigidity.
  • Plant-based: Made from materials like hemp, flax or wood fiber, plant-based insulation is less energy intensive to produce and it even captures carbon while installed. It’s less common than other types of insulation.

Learn more about the various types of insulation here: Loft Insulation: The Snugg 2024 Guide.


Is spray foam insulation safe?

Spray foam insulation can be safe if it’s installed correctly in a suitable location. However, if installed incorrectly it can release toxic gases and carcinogens that can potentially cause health issues, from skin irritation and asthma to cancer.

What are the disadvantages of spray foam insulation?

Potential disadvantages of spray foam insulation include:

  • Difficulty getting a mortgage (lenders are reluctant to lend on homes with spray foam insulation)
  • Health issues (skin and respiratory problems can occur due to the chemicals in spray foam insulation)
  • Environmental damage (spray foam insulation isn’t recyclable, and it can release greenhouse gases that are over 1,000 times more harmful than carbon dioxide)
  • Ventilation issues (spray foam insulation covers all gaps, which can lead to dampness, condensation and wood rot)
  • Lower home valuation (a home with spray foam insulation is less attractive to buyers)

Is spray foam insulation good or bad?

Spray foam insulation is a good insulator in terms of keeping a room warm or cool. But its many downsides outweigh the benefits. These include, making it more difficult getting a mortgage, potential health issues, environmental damage, ventilation issues and a lower home valuation.

What are spray foam insulation pros and cons?

Pros of spray foam insulation:

  • Quick to install
  • Good insulation properties
  • Expands to fill gaps
  • Long lifespan (up to 80 years)

Cons of spray foam insulation:

  • Expensive to install
  • Messy to install
  • Difficult to remove
  • Difficulty getting a mortgage  
  • Potential health issues
  • Unsustainable/non-recyclable material
  • Ventilation issues
  • Lower home valuation

Is spray foam insulation flammable?

Yes, spray foam insulation flammable. But some spray foam insulation is treated with flame retardants which increases the temperature that it will combust.

What is spray foam insulation made of?

Spray foam insulation is typically made of unsustainable petroleum-based materials such as polyurethane which is difficult to recycle and usually ends up in landfills.

Spray foam insulation can also release harmful chemicals such as isocyanates during and after installation if not properly installed, which can cause various health issues including skin irritation and asthma.

The spray guns used during installation often use hydrofluorocarbons (HFCs) as blowing agents, which are potent greenhouse gases that contribute significantly to global warming.

Can spray foam insulation cause mold?

Yes, spray foam insulation can lead to mold growth if it’s installed incorrectly since it can trap moisture, reduce ventilation and increase humidity.

Why is spray foam insulation making homes unsellable?

Spray foam insulation is making some homes more difficult to sell due to its various downsides, such as being difficult to remove and hiding potential structural issues. This has led to many mortgage lenders refusing to lend on homes with spray foam insulation installed, which in turn is reducing the number of people who can afford to buy these homes without a mortgage. Additionally, knowing that a home with spray foam insulation will be harder to sell in future is putting off potential buyers today.

Is spray foam insulation legal?

Yes, despite its various downsides and potential health risks, spray foam insulation is legal to buy and install.

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