Should you buy a house with spray foam insulation?

A survey can record that the foam is there, but not the condition of the timber beneath it. RICS says a timber roof covered in spray foam cannot be fully seen or inspected and leaks may go unnoticed; it does not say the foam has to be removed for an inspection^[1].

The RICS Home Survey Standard sets how much of the roof space is inspected at each of its three survey levels^[3]. The standard's Level 3 description does not mention spray foam, so what gets reported depends on the surveyor^[3]. The surveyor may recommend an independent specialist report^[1]. Before you book, ask whether the surveyor will go into the loft and comment on the foam.

The PCA's protocol is a non-invasive visual method with three possible conclusions: risk not significantly increased, risk increased (get further advice), or not enough information to say^[9]. Moisture readings need reading in context. In one case file, Buying with old foam on the slates: the lowest reading came from failed timber, the wall plate read just 11.6% but came apart under light finger pressure where examined.

Check before you commit, because lenders differ. In the BBC's survey of the 20 largest lenders (November 2024), five would not lend where spray foam is in the roof space, two would not usually lend where it is significant, and five decided case by case on the valuer's report^[2].

Published criteria vary too. Nationwide's criteria (read 19 Oct 2026) say its valuer declines at first, and Nationwide then reconsiders on a full evidence pack or an invasive inspection by a chartered building surveyor^[10]. The Co-operative Bank's criteria (2 Mar 2026) can consider open-cell foam with documents, a product approval and a transferable insurance-backed warranty^[11]. The government's position (August 2025) is that spray foam alone should not automatically prevent lending, with cases decided individually after a survey^[14].

Tell your broker or lender about the foam early and ask what evidence its valuer will want. The dated lender table is on can you get a mortgage on a house with spray foam?.

If you want to know what the foam may be hiding before you commit, an independent inspection before exchange gives you evidence while the terms are still open. Choose who does it carefully. The consumer guide published by the PCA, the manufacturers' association and partners gives five tests for an assessor: knows the spray foam inspection protocol, belongs to a professional or trade body, is insured, is experienced, and is impartial, meaning free of commercial interest or declaring any interest from the start^[15].

That matters most if removal comes up. Warwickshire Trading Standards advises getting an independent surveyor's report before agreeing to removal, which can cost thousands and may be unnecessary^[7].

Be clear about what any inspection can do. It can record where the foam is, what it is sprayed onto, the state of the ventilation and the timber that can be reached; it cannot assess timber the foam conceals without exposing it^[1]. An independent inspection is evidence for your own decision: whether to go ahead, renegotiate or walk away. It is not a report for a lender, and no one can promise what a lender will do.

Yes, and walking away is also a legitimate outcome. The options, and what to watch:

• Price. No study or dataset on how much spray foam affects a home's price was found for this guide; RICS says only that it may affect a surveyor's opinion of value^[1]. Base any renegotiation on what the survey and inspection actually found.
• A retention. Your conveyancer can advise on holding back part of the price until agreed work is done. Nationwide's criteria do not mention retentions^[10], so check with your lender before relying on one.
• Removal by the seller before completion. RICS warns that removal could damage the structure the foam was applied to^[1], and the Energy Saving Trust says that structure may then need replacing^[16]. Few lenders publish anything about removed foam: Nationwide's criteria do not mention it^[10], and Accord Mortgages (checked 20 Oct 2026) lists spray foam as unacceptable even where it was later removed^[17]. Removal also hides what the roof was like with the foam in place.

If the seller does agree to remove it, agree in writing beforehand what evidence you will receive.

Evidence of what was done and what was found underneath. No official guidance on spray foam removal was found for this guide. A PCA membership category for removal contractors was reported in the trade press in late August 2026; it is a trade-body membership scheme^[18].

Ask for:

• the removal firm's invoice and a description of what was removed, and from where
• photos of the roof before, during and after removal
• what condition the timbers and underlay were in, and any repairs made
• whether all residue was cleared and the eaves ventilation restored
• how the loft has been re-insulated

One published lender list shows the kind of evidence asked for: Legal & General's later-life criteria (June 2026) accept removed foam only where a PCA member "or similar" removed it, residue was cleared, a structural engineer or chartered surveyor reported on the roof, repairs were done and building control signed off^[8]. Be cautious with a report written by the firm that did the removal: the Financial Ombudsman has discounted such reports as not independent^[19]. More on this in after spray foam removal.