Why spray foam is holding up your mortgage

If a surveyor has found spray foam on the underside of your roof, you're in a large group. The Insulation Manufacturers Association estimates about 250,000 UK homes have it.

What the surveyor is worried about

Foam sprayed onto rafters covers the timber roof structure. A surveyor can't see whether the timbers are wet, rotting or damaged underneath, and a slow leak can go unnoticed for years. RICS guidance says a surveyor who finds spray foam may ask for an independent specialist report, and that report can change the valuation.

The worry is not theoretical. A Property Care Association survey found 35% of spray foam homes had at least one problem, and in 27% of cases the foam had to be removed or the roof replaced.

Why lenders say no

In March 2026, Homebuilding & Renovating reported that only about a quarter of mortgage lenders, and no equity release providers, would lend on a home with spray foam. Each lender sets its own policy. Some refuse homes with spray foam outright. Others will consider it with a specialist report or proof of a correct installation. UK Finance has said lenders are cautious because the paperwork for many installations is missing.

Your options

1. Get a specialist report. An independent inspection of the foam and timbers. Some lenders accept a good report instead of removal.
2. Try a different lender. A broker can find lenders that accept spray foam with conditions.
3. Remove the foam. The most certain fix. Make sure you get the paperwork your lender will ask for (see what paperwork to ask for).

If you're selling, the same problem moves to your buyer's lender. See selling a house with spray foam.