Spray foam and lenders
How should a buyer separate spray foam on the rafters, nail heads the foam covers and a roof covering the foam stops the survey seeing when all three are mentioned together?
Separate what was seen from what the foam hides. Spray foam on the rafters was noted because it is there on the timber. Nail heads the foam covers were not inspected, because the foam is in the way. The roof covering, which that foam stops the survey seeing from inside, was not judged from the underside. The three belong together only as a limit. Foam on the rafters is not a verdict on the nails and not a verdict on the slates or other covering. The survey has recorded the obstruction. It has not decided that the hidden covering is sound.
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?
Nail heads are the fixings that hold the covering to the battens or the boarding. Once foam coats them, the surveyor cannot see whether they are rusted, short or missing. The same coat blocks the underside of the covering, so laps, felt and boards stay unseen from the room. Outside, a look at the roof face is a different view and was not created by naming the foam. The report is telling you the inside inspection stopped at the foam. It is not telling you the covering passed or failed.
Tell the solicitor the foam hid the nail heads and the underside of the covering. A roofer would need a separate instruction, and a way of seeing those parts, before anyone prices a repair or a clearance. Do not tell a lender the roof was inspected through the foam. The survey has not sampled the foam and has not uncovered the fixings. Keep the three items labelled as seen, hidden and hidden.
What should you ask your surveyor?
- Was the spray foam itself seen on the rafters?
- Which nail heads stayed covered, so they were not inspected?
- Did the foam stop any view of the covering from inside?
What are the typical next steps?
- Split seen foam from unseen nails and unseen covering.
- Tell the solicitor the underside was blocked by the foam.
- Do not brief a lender that the hidden covering was cleared.
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
Does foam on the rafters mean the covering was renewed?
No. Spray foam is an added coating inside the roof. It does not say when the covering was laid, and it stops the survey seeing that covering from the room. Nail heads under the foam were not inspected. The report has not decided that the outside roof is new or old. Those facts stay hidden with the fixings.
Can a binocular look from the garden replace the hidden nails?
A distant look can note the outside face. It does not see nail heads the foam covers on the inside, and it is not the inspection the foam prevented. The survey has not claimed that an outside glance tested the fixings. The nails remain unseen. The covering's underside remains unseen as well.