Spray Foam Insulation in Lofts: Mortgages, Surveys and Removal

Spray foam insulation was sold to a great many UK homeowners as a modern, mess-free way to insulate a loft, often through door-to-door or phone sales. Some of those homeowners have since found that the foam causes problems when they try to remortgage, release equity or sell.

This guide explains what spray foam is, why surveyors and lenders are wary of it, and what you can do if it is already in your roof.

What Spray Foam Insulation Is

Spray foam is a liquid, usually polyurethane, that is sprayed onto the underside of the roof between and over the rafters. It expands and sets into a solid layer. Unlike conventional loft insulation, which is laid on the ceiling and leaves the roof space cold and ventilated, spray foam insulates at the roof itself.

Why Lenders and Surveyors Are Wary

The timbers cannot be inspected

A surveyor or valuer needs to see the condition of the rafters, battens and underside of the roof. Once they are covered in foam, that is not possible without cutting it away. Faced with a roof they cannot assess, many will flag it as a risk.

Moisture can be trapped

Roofs are designed to manage moisture. Foam applied without proper attention to ventilation and the roof's membrane can hold moisture against the timbers, and over time that can lead to decay. Not every installation causes problems, but the concern is enough for many lenders to want reassurance.

Closed cell foam can bond the roof together

Rigid foam sprayed directly onto tiles, slates or felt can glue them in place. That makes later roof repairs harder and can mean tiles and battens cannot be reused when the foam is removed.

Quality varies

Industry bodies have acknowledged that the standard of installations has been mixed, which is why surveyors, lenders and manufacturers have worked on inspection protocols to help tell good installations from bad ones.

Mortgages, Remortgages and Equity Release

There is no single rule. Lenders set their own policies, and they change over time.

• Some lenders decline properties with spray foam in the roof.
• Many consider it case by case, usually asking for the installer's documentation and an independent inspection report on the roof.
• Equity release providers have tended to be among the strictest.
• If one lender says no, another may take a different view, so it is worth speaking to a mortgage broker.

What to Do If You Already Have Spray Foam

What Removal Involves

Spray foam removal is specialist work. The foam is cut and scraped away from the rafters and the underside of the roof, which is slow and messy, particularly with closed cell foam. Once it is off, the timbers can be inspected and any decay dealt with. Depending on how the foam was applied, the roof covering, battens or membrane may need attention, and ventilation may need to be restored. Removal should be followed by a report or evidence your lender will accept.

If You Are Being Offered Spray Foam

• Do not be rushed. High-pressure doorstep or phone sales are a warning sign.
• Check with your lender before agreeing to anything that affects the roof.
• Get independent advice from a surveyor who is not connected to the installer.
• Consider conventional insulation. For most lofts, mineral wool on the ceiling to 270mm is effective, inexpensive and does not raise the same questions with lenders. See how thick should loft insulation be.

Back to Conventional Insulation

Once spray foam has been removed and the roof signed off, the loft can be insulated the conventional way: mineral wool laid between and across the ceiling joists, insulation reaching the walls, and the eaves left open so the roof can breathe. Our guides to eaves ventilation and insulating around lights, cables and tanks cover the details, and our loft insulation installation page explains how we lay it.

Frequently Asked Questions

Will spray foam insulation stop me getting a mortgage?

Not necessarily, but it can make it harder. Lenders' policies vary: some decline properties with spray foam in the roof, while others consider them case by case, usually with an independent inspection report and the installation paperwork. If one lender refuses, another may not.

What is the difference between open cell and closed cell spray foam?

Closed cell foam is dense and rigid and bonds firmly to the roof, which can make the tiles and battens difficult to repair or reuse. Open cell foam is softer and lets some moisture pass through it. Both cover the timbers, which is why surveyors find them hard to assess.

Why do surveyors not like spray foam?

Because they cannot see or check the condition of the rafters, battens and underside of the roof through it, and because foam applied to a roof without proper ventilation or a suitable membrane can trap moisture against the timbers, risking rot over time.

Can spray foam be removed from a loft?

Yes. Removal is specialist work, often involving cutting and scraping the foam from the rafters and roof, then inspecting and repairing timbers and restoring ventilation. Closed cell foam bonded to tiles can be much harder to remove than open cell.

What should I do if a salesperson offers spray foam?

Take your time, get independent advice and check with your mortgage lender before agreeing to anything. The Royal Institution of Chartered Surveyors published a consumer guide on spray foam insulation in 2023, which is a good starting point.

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