This information should not be relied upon as legal or professional advice. Read the disclaimer.

Recent media and industry reports suggest some homeowners have found it difficult to remortgage or sell properties that have spray foam insultation.

If installed incorrectly, spray foam insulation may lead to condensation which can affect a roof structure.

This article focuses on England. An article by the Scottish Parliament Information Centre provides information on the use of spray foam insulation in Scotland.

What is spray foam insulation?

Spray foam insulation is one method to insulate a home to stop heat from escaping. This can improve its energy efficiency and reduce energy bills.

It is a form of liquid insulation that is applied with a spray gun. It expands to fit the area available and sets to form an insulation layer. It is typically used to insulate roofs, lofts and attics. Spray foam insulation can come in two forms:

  • Open cell: remains soft after setting. It is not as prone to condensation as closed cell spray foam. However, it does not provide the same level of insulation as it is not as dense.
  • Closed cell: is rigid once set. It is a better insulator than open cell spray foam. However, it is also a vapour barrier that can reduce ventilation.

Spray foam insultation was one of the measures covered by the government’s Green Homes Grant scheme. The scheme, which closed in March 2022, covered up to two-thirds of the cost of works to improve the energy efficiency of homes.

Potential problems with spray foam insulation

Spray foam insulation has been used in many homes for decades, but recently, problems in timber-framed roofs have been reported. If incorrectly installed or used inappropriately, spray foam insulation might:

  • reduce air circulation and ventilation within a roof space.
  • lead to dampness and condensation on the underside of a roof because it forms an air barrier and stops moisture from escaping.
  • place timber-framed roofs at risk of decay.

Spray foam insulation can also be difficult and costly to remove. According to the website Checkatrade, the cost of removing spray foam insulation from the roof of a three-bedroom detached house is around £3,200 (or £40 per square metre).

The Royal Institution of Chartered Surveyors (RICS) said the presence of spray foam may affect a surveyor’s valuation of a property, for example, if it has been applied incorrectly. The Home Owners Alliance (HOA), a consumer group which advises homeowners, says that because spray foam covers a roof’s structure, surveyors appointed by mortgage lenders may find it difficult to inspect the condition of individual roofs and identify risks.

Industry guidance

In November 2021, the Residential Property Surveyors Association (RPSA) and Property Care Association (PCA) published (now withdrawn) guidance (PDF). The guidance said that, without technical information, it was “unlikely” that surveyors could “comment on the condition of the timber roof structures or speculate on risk”.

That guidance was withdrawn in October 2022 for a “full review”. The PCA and RPSA said they have been working with lenders, surveyors and the spray foam industry to develop inspection protocols and installation procedures.

In March 2023, the PCA published an inspection protocol for surveyors to help them assess spray foam risks inside pitched roofs. It said the framework will help surveyors assess the condition of individual roofs instead of having to make decision on spray foam “just being there”. The PCA also developed training to help surveyors evaluate properties with spray foam and recommend appropriate actions.

The PCA said the next step would be for the spray foam industry to create a “system of controls” for suppliers and installers to allow “installations to be measured and verified” against product approval certificates.

Guidance for homeowners considering spray foam

The HOA has advised homeowners to “avoid installing spray foam roof insulation” until the issues are resolved. It has advised homeowners who wish to install spray foam insulation to use a member of the National Insulation Installers.

The RICS has published guidance for homeowners who are considering installing spray foam insulation. It advises homeowners to obtain “independent expertise, commercially separate from the installer and manufacturer” from a qualified professional to help them determine whether spray foam insulation is suitable for their property. The PCA also advises homeowners to carry out appropriate checks to determine whether spray foam is suitable for their roof.

How has the UK Government responded?

In June 2022, the government said it had no plans to intervene where property values or access to mortgages had been affected because 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.

In March 2022, the government said consumers who believe they have been misled may be able to seek redress under the Consumer Protection from Unfair Trading Regulations 2008 (see below). All traders have to adhere to these regulations.

What can affected homeowners do?

Request and keep paperwork

The RICS advises homeowners to keep paperwork from their installation “to assist should you decide to sell or remortgage the property”. This includes independent test certificates which are awarded to spray foam products by organisations such as the British Board of Agrement (BBA).

This may help a surveyor assess the work done.

Look for another mortgage lender

The HOA said some lenders may offer mortgages to homeowners with spray foam insulation. Certain criteria about the type of spray foam and its installation may need to be met.

Most lenders will ask a surveyor to inspect the insulation and make mortgage decisions based on that survey.

Consider removal

Qualified professionals may be able to advise affected homeowners about removing spray foam insulation. Checkatrade provides estimates of the cost.

Checkatrade advises homeowners against removing insulation themselves because it could “damage tiles, electrics and other materials”. It says some spray foam is “toxic to touch and breathe in”.

Raise a complaint

Affected homeowners may wish to review the terms on which they were sold the insulation and raise any issues with their installer or accredited oversight body in the first instance.

All works completed under the Green Homes Grant scheme had to be undertaken by a TrustMark-registered installer. TrustMark has a dedicated dispute resolution process.

If a consumer believes they were misled or their installer omitted important information in such a way that was likely to deceive them, they may wish seek redress under the Consumer Protection from Unfair Trading Regulations 2008.

The Library briefing, Legal help: where to go and how to pay, provides advice on sources of legal information.

Photo by Super Straho on Unsplash

About the author: Felicia Rankl is a researcher at the House of Commons Library, specialising in areas of building regulations and planning.


The Commons Library does not intend the information in this article to address the specific circumstances of any particular individual. We have published it to support the work of MPs. You should not rely upon it as legal or professional advice, or as a substitute for it. We do not accept any liability whatsoever for any errors, omissions or misstatements contained herein. You should consult a suitably qualified professional if you require specific advice or information. Read our briefing for information about sources of legal advice and help.