Spray Foam Insulation - Does it Work?
What is Spray Foam Insulation?
Spray Foam Insulation is an alternative to conventional home insulation materials, such as PIR, fiberglass and mineral wool. The foam is sprayed into cavities in your home, such as those between roof timbers, timber frames and floor joists. It expands and hardens, creating an air-tight, insulating barrier.
There are two types of foam, closed-cell and open-cell. Closed-cell is more dense and rigid, whereas open-cell is lighter and less dense.
Potential Problems with Spray Foam Insulation
There are a number of reported issues with spray foam insulation. For the time being, let’s assume spray foam insulation has been installed in your home correctly and to a compliant standard - these are the issues you could still face:
Due to the airtight seal it creates, the insulation prevents natural air circulation, which can lead to trapped moisture and, therefore, rot and decay in wooden roof timbers, timber frames and floor joists.
Over-expansion of the foam, particularly with closed-cell foam, can exert too much pressure on the surrounding structure and damage it over time.
When the foam expands and hardens it becomes difficult to remove, which makes structural surveys and inspections challenging to complete.
Now consider that you have had spray foam insulation installed in your home to a sub-standard - these are the issues that may present themselves to you:
If the foam is sprayed such that gaps are left in the cavities, heat can escape through those gaps regardless of how good the rest of the installation is, like air escaping from a punctured tire.
Due to the spray foam containing harmful chemicals, it can be a dangerous process for both the installer and homeowner without adequate protection.
Regardless of how well spray foam is installed, installing it is a messy process and the foam is often non-recyclable, sometimes making it a less sustainable option than advertised.
Can Spray Foam Insulation Affect Mortgages and Equity Release?
The only way to get a definitive answer to this question regarding your own home is to speak to your lender.
Although it has been widely reported that it is impossible to get a mortgage for or release equity from a home with spray foam insulation, the Insulation Manufacturers Association says, “Mortgage lenders will assess each project on its merits and where the installation has been carried out by a registered contractor, with all the information available for the mortgage company to confirm the work meets all necessary standards, this often leads to a positive outcome.” (“Why it is not necessary to remove spray foam - IMA”)
In an article for the House of Commons Library, a consistent message is that the ability to get a mortgage for or release equity from a home with spray foam installed depends on the type of foam used, the quality of its installation and the presence of relevant paperwork provided by the installer. (Rankl)
Nonetheless, issues often arise, as experienced by one home owner in the video below.
Appropriate Use of Spray Foam Insulation
There are benefits to spray foam insulation besides reducing heat loss and, therefore, reducing the cost of energy bills. When installed correctly and in an appropriate space, it can create a continuous air barrier that prevents drafts, and due to its liquid form it is incredibly versatile, which is ideal for difficult-to-reach or oddly-shaped cavities.
HouseFix Can Help You
As other sources advise, removal of spray foam insulation is not always necessary. But if removal is the best solution for you, head to Spray Foam Insulation for more information on how HouseFix can help you.
Sources
Rankl, Felicia. “Spray foam insulation and mortgages.” The House of Commons Library, 5 February 2024, https://commonslibrary.parliament.uk/spray-foam-insulation-and-mortgages/. Accessed 22 December 2025.
“Why it is not necessary to remove spray foam - IMA.” Insulation Manufacturers Association, 2024, https://insulationmanufacturers.org.uk/spray-foam-removal/. Accessed 22 December 2025.
