Spray foam and lenders
From the loft a ridge of spray foam fills the underside of a valley. What lining of that valley can no longer be seen?
The lining under that valley can no longer be seen, because a ridge of spray foam fills its underside. From the loft the foam occupies the junction where an underlay, felt or metal valley lining would otherwise show. The survey has recorded the foam ridge. It has not peeled it back, has not identified the lining now buried, and has not decided that the valley is watertight or leaking. RICS notes that spray foam can hide roof timbers and that lenders ask their own questions. This inspection does not answer those questions for them, and it does not see through the foam.
Last reviewed 24 October 2026. Written for buyers in England and Wales unless this answer says otherwise. No named surveyor has signed this page. It is general guidance, not a report on your house, and not legal advice.
What is the fuller explanation?
A valley collects water from two slopes and needs a continuous lining to carry it. Foam sprayed along the underside covers that lining and the rafters beside it. An even ridge is a thickness of foam, not a view of lead, felt or membrane. The survey can say the lining is concealed. It cannot say the lining is intact, torn, or missing, and it cannot say the timbers under the foam are sound. Looking from the loft does not become a valley inspection once the foam is in the way.
Pass the foam ridge to your solicitor with the rest of the roof note, and expect a lender to ask what the survey could not see. RICS says lenders have their own questions about spray foam. The survey does not set that policy and does not recommend a removal price. If someone must know the valley lining, that is a roofer's job with the foam still acknowledged as the thing in the way, not a sentence the report can now add.
What should you ask your surveyor?
- Which part of the valley lining is covered by the foam ridge?
- Could you see any underlay, felt or metal at the edges of that foam?
- Are you recording a hidden lining rather than a verdict on the valley?
What are the typical next steps?
- Treat the valley lining under the foam as unseen.
- Tell the solicitor the survey could not see through the foam ridge.
- Let the lender ask its own question rather than inventing a lining.
Costs vary with the building and with who you instruct. Where this page does not cite a published figure, ask the surveyor, a relevant specialist, or your solicitor for a written quote. Do not treat a forum average as the price.
Also asked about this
If the foam ridge looks tidy, has the valley been shown to shed water?
No. A tidy ridge describes the foam, not the lining under it. The survey has not run water down the valley and has not seen the underlay, felt or metal that should carry it. Appearance from the loft is not a weathering test.
Does the survey tell a lender to accept or refuse this roof?
No. RICS notes that lenders have their own questions about spray foam. The home survey records that the valley lining is hidden. It does not set the lender's rule and it does not turn the foam into a pass or a refusal.