Experts Warning to Oxfordshire residents on spray foam insulation

Changes in the mortgage lending criteria has seen an increase in properties rejected where spray foam insulation has been used. Where this has created trapped moisture, this can cause structural and damp problems, rendering the property unmortgageable, warns finance expert Dan Stevens.

And this presents a stark warning to any Oxfordshire resident who has had sprayed polyurethane expanding foams used in lofts and cavity walls, with mortgage companies refusing loans in some instances where it’s created these structural concerns.

There has been a concerning increase in mortgage rejections due to the recent use of spray form insulation in lofts, with the lenders surveys revealing cases of damp giving structural concerns.

Dan Stevens

In a lot of cases, this was due to poorly executed installation, often sold by companies cold-calling on vulnerable homeowners. And as yet, the Government are not assisting anyone who has this problem.

Of course the irony is, back in 2021 the UK government pushed their £2bn plan to offer the home insulation Green Homes Grant of up to £5,000 per household in England. This was partly driven to restart the construction industry, and also enable homeowners an opportunity to improve energy efficiency and reduce the demand on natural resources and reduce energy bills.

While it was only allowed via accredited regional suppliers, the common work undertaken was using spray polyurethane foam for loft insulation. Which means in some cases, the grant was spent on Government approved companies advice, resulting in a property that cannot be sold or remortgaged with another mortgage lender.

In June 2022, the Government said it had no plans to intervene where property values or access to mortgage finance had been affected as a result of spray foam insulation installed using Green Homes Grant vouchers, stating that:

  • The availability and terms of mortgages are issues for lenders.
  • It is the responsibility of the installer and homeowner to decide whether to proceed with using spray foam insulation.
spray foam installation in loft
Spray foam Insulation may have been advised and can now cause issues with mortgage lender surveys

What Are The Problems Associated With Spray Foam Insulation?

From a sustainability standpoint, the biggest problem with spray foam is that it is made of toxic chemicals, some of which will pollute the indoor air long after owners take home occupancy.

And once it is applied to a substrate, it is challenging to remove it. And even though it’s a great tool to stop homes from wasting energy (in turn, helping the environment), the majority of spray foam insulation is just not eco-friendly.

In fact, it is 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, it will inevitably become a thing of the past.

It isn’t just what spray foam is made from either – applying it has environmental risks that are hard to ignore. When you apply liquid foam, you need to use a ‘blowing agent’. These are usually made from a mixture of hydrofluorocarbons, and therein lies the problem.

But in the short term it is the recent reports of banks refusing to lend on properties containing spray foam insulation are a major issue for homeowners. Where moisture management has not been addressed in the work, structural roof timbers are at risk of damage or failure. This not only fails building inspections, but also affects property values.

Like many things, the results of the poor application can bring a system into disrepute, and with many DIY spray foam kits now becoming available, one could rightly understand a cautious view of the results of the inexpert application by DIYers or inexperienced companies. 

One DIY expert, David Dooley of The Big Idea suggests that foil backed insulation boards with a membrane, are a preferable alternative as an insulating layer until more research has been carried out.

Can Spray Foam Insulation Cause Roof Damage

Spray foam insulation, when done correctly, shouldn’t cause any significant damage to your roof or timber structure. However, if you have opted for “closed-cell” spray foam in your roof, you run certain risks.

The best DIY insulation to use is insulation boards and membrane, which leave space for air to circulate and also can easily be removed

David Dooley


a loft extension with spray form insulation

Which Types Of Foam Spray Are Available?

Sprayed insulation has been available for the past 30 years or so. There are two basic variants, closed cell and open cell. To begin with, sprayed materials were often formulations of urea formaldehyde foam.

Still, these have given way to improved materials using isocyanate and polyol resin that, when mixed together, expand around 60 times and, in some cases, up to 100 times. The material is usually sprayed on under pressure to a thickness of up to 300mm.

Open-celled products are reasonably vapour-permeable and often used for thermal insulation purposes. Closed-cell products are used in cases where a manufacturer perceives a competitive advantage by extending the life of a roof with defective coverings, corroded fixings or leaks.

Closed-cell products can also be used to improve airtightness – and because the insulation line and the airline can be combined, there are arguments that the system is more efficient than insulating at ceiling level.

Property Care Association Stance

Spray foam insulation within domestic roof voids continues with no regulation. There are (of course) initial benefits for the homeowner, such as providing extra insulation. However, for many surveyors and property professionals, the sprayed foam does pose an issue when trying to evaluate and report on the condition of a roof.

Sadly, many installations are poorly executed and without proper consideration of moisture management within the property, leaving structural roof timbers at risk of damage or failure. With the additional tightening of lending criteria, for many homeowners, these improper spray foam installations can even risk the mortgage ability of the property.

As with any trade organisation the Property Care Association have commissioned a study into this subject to look at both sides of the argument and the conclusion is written here.

The Residential Property Surveyors Association have also taken the same course of action in investigating the pros and cons of foam spray insulation and have come to almost the same conclusion and are dealing with issues on a case by case basis.


Why Do Mortgage Companies Dislike Foam Insulation?

The main structural concern is foam insulation seals the roof space with this material, air circulation can be restricted to the roof and timbers. This can lead to condensation, which can eventually lead to the rotting of the wooden roof supports. The closed-cell foam version also sets very hard.

Does Spray Foam Insulation Prevent You From Obtaining A Mortgage?

One equity release specialist as recently as January 2022 said that some mortgage lenders might accept a house with spray foam insulation. However, they would need a valuer’s approval, and specific criteria about the type of spray foam would need to be met.

What Can Affected Homeowners Do?

If you have been turned down for a mortgage, then looking for another lender is the first step as some out there that have given new and updated mortgages to homeowners. However, they would need a valuer’s approval, and specific criteria about the type of spray foam would need to be met. Most lenders will rely on a survey to identify the insulation used and make mortgage decisions based on that survey.

Affected homeowners are advised to keep any paperwork and guarantees from their installation. This may help a surveyor assess the work done. Alternatively, having the foam insulation removed is not cheap but would increase the chances of being approved.

Also, concerns over spray foam might not be fully supported by examination of the evidence, and failures could be due to a combination of other causes rather than the foam itself. For example, high humidity, poor ventilation or the presumption that a roof covering in poor condition can somehow be made sound by a sprayed coating.