Wall ties and cavity insulation
The seller mentions a cavity-insulation guarantee and it is not in the pack. Does the survey create that guarantee?
No. The survey does not create a cavity-insulation guarantee. The seller mentions one, and it is not in the pack, so the document was not read and its terms were not checked. A home survey can note a cavity where it is visible and can record that a guarantee was claimed but missing. It does not issue, extend or verify that guarantee. You still need the paper itself. A sentence in the report is not the insurer or the installer standing behind the fill.
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?
Cavity insulation is hidden once the wall is closed, so a guarantee is the paper trail for who installed it and what they promised. Without the document, the surveyor cannot see the term, the address it covers or any exclusion. Drill holes, a changed wall finish or the seller's memory are not that document. The visit did not core the wall and did not identify the fill by a laboratory test. The gap in the pack stays a gap. The survey is not a replacement certificate.
Ask the solicitor to require the guarantee from the seller, including any schedule that names this house. If it never arrives, you know the claim was only verbal. An insulation body or the original installer is the route to a copy, not the surveyor. Tell a lender the guarantee was mentioned and not produced. Do not describe the cavities as guaranteed. The survey has not seen the fill and has not created cover for it.
What should you ask your surveyor?
- Was the guarantee document in the pack and read?
- Does the survey issue a cavity-insulation guarantee of its own?
- Has the fill been sampled, or only a missing paper recorded?
What are the typical next steps?
- Treat the guarantee as missing until the seller produces it.
- Ask the solicitor to require the document that names this house.
- Do not describe the cavities as guaranteed on the survey wording.
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
Can the seller's spoken claim stand in for the missing paper?
No. A spoken claim is how the guarantee was mentioned, and the pack did not contain it. Memory does not show the term, the property or the installer. The survey recorded the absence. It did not convert the conversation into a document. Until the paper is produced and checked, there is no guarantee in hand for this house.
Has this visit sampled the insulation inside the cavity?
No. The survey did not drill the wall or test the fill. Cavity insulation, if it is there, stays hidden behind the leaves. The finding is that a guarantee was mentioned and is not in the pack. That is a paperwork gap. It is not a laboratory description of what is in the cavity.