Wall ties and cavity insulation
Old borescope holes sit only at damp-course level. Why can those holes not speak for the ties on the upper floors?
Those holes cannot speak for the ties on the upper floors. Old borescope holes sit only at damp-course level, so someone once looked, or drilled, near the base of the wall, not at the storeys above. Ties can differ by height, by age and by how wet each band of the cavity has been. A low-level hole does not describe the metal higher up. This survey did not make the holes, did not look through them, and did not test the upper ties. The holes are old marks. They are not a result for the floors overhead.
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 borescope sees only the small cone of cavity in front of its hole. Even a careful survey at damp-course level would say nothing automatic about the first floor or the gable head. These holes are old, so this visit cannot even claim that low-level look as its own. The drillings might have been for ties, for insulation, or for a damp check. The survey did not identify which. What it can say is the limit: nothing in those holes reports the upper floors.
If upper-floor ties are the lender's question, say the old holes are only at damp-course level and that this visit did not scope them or the walls above. A fresh test at the upper levels would be new work. Do not let a row of filled holes near the ground be photocopied into a whole-house tie certificate. The upper ties remain unexamined.
What should you ask your surveyor?
- Do the old holes reach above damp-course level?
- Did this visit look through them or test the upper ties?
- Is a low-level drilling being treated as a whole-wall result?
What are the typical next steps?
- Refuse to let damp-course holes speak for the upper floors.
- Say this visit did not scope the holes or the walls above.
- Instruct a fresh upper-level test only if one is actually required.
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 filler in an old hole mean a tie was found there?
No. Filler shows a hole was made and closed. It does not show a tie, a failed tie, or a clear cavity. The survey did not look through the holes and did not make them. Even at damp-course level they are not this visit's result, and they still cannot speak for the floors above.
Could the same ties run from the damp course to the eaves?
They might, and they might not. That is the point of refusing the leap. Cavity ties are not proved continuous by a hole at the bottom. This survey did not test the upper floors. Do not tell a lender the eaves ties match the base. Nobody on this visit saw them.