Spray foam and lenders
How should a buyer separate spray foam, carried across where the party wall should be and fire stopping the foam may be covering when all three are mentioned together?
Separate the spray foam, the line where the party wall should be, and the fire stopping the foam may be covering. The foam was seen running across that line in the loft. The stopping, if it lies under the foam, was not seen and was not tested. The survey has not confirmed that a barrier is present, continuous or missing. It has recorded that foam crosses the place you would expect the party separation to show. Fire performance of that junction stays undecided. The three things must not be written as one fact.
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?
In a terrace or semi, the party wall should rise through the loft and separate the roofs. Fire stopping at that line is there to close gaps. Spray foam applied across the junction can bury the top of the wall and any stopping, so a surveyor sees a continuous layer instead of a visible barrier. Continuity of foam is not proof the barrier was omitted, and it is not proof the barrier is still there. It is proof the survey could not see the detail.
Tell the solicitor the foam crosses the party line and that fire stopping was not inspected. Ask what the lease or the deeds say about the party wall, without treating the survey as a fire certificate. If the junction needs to be known, a specialist who can look at fire stopping is a further instruction. Do not cut the foam out yourself to check. The home survey has not done that, and it has not declared the barrier sound or absent.
What should you ask your surveyor?
- Was the top of the party wall visible, or only foam across that line?
- Did the report say fire stopping was seen, or that it might be covered?
- Who, if anyone, has been asked to inspect the junction?
What are the typical next steps?
- Keep the foam, the party-wall line and the fire stopping as three items.
- Do not treat covered stopping as either present or missing.
- Ask the solicitor about the party wall, and a specialist if the junction must be known.
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
Was the fire stopping seen under the foam?
No. The foam may be covering it, and the survey did not see it and did not test it. Spray foam carried across the party-wall line is what was visible. A hidden barrier was not confirmed and was not ruled out. The stopping stays undecided.
Does foam across the line prove a barrier is missing?
No. It proves the line is covered, so the survey could not see whether fire stopping is there. Missing and buried look the same from the hatch. The report separated the foam from the stopping for that reason. Do not collapse them into a single claim that the barrier has gone.