Wall ties and cavity insulation
Can slumped cavity insulation be written up as if the wall ties had failed?
It should not be. Slumped or poorly installed insulation is a fill that has settled or bridged, often leaving a cold band or a damp patch. Failed ties are metal that no longer ties the leaves, often with cracks in regular courses. A home survey that cannot see inside the cavity should not swap the names. The Energy Saving Trust’s conditions are about whether a cavity should be filled, not a tie test.
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?
Both can be present in an early cavity wall, which is why the words get mixed. A cold band inside, with no crack outside, is a poor clue for ties and a better clue for the fill or for moisture. Horizontal cracking, with or without insulation, is the clue that sends you to a tie inspection. The Property Care Association would still want the moisture explained. Neither body publishes a price for emptying a cavity.
If you are offered extraction of insulation and replacement of ties in one quote, ask which finding each line answers. The survey may have mentioned only one of them. There is no RICS combined tariff. Do not fill a cavity the survey has already said is cracked until someone competent has looked at the ties.
What should you ask your surveyor?
- Are you describing the insulation, the ties, or both?
- What could you actually see: a crack, a cold patch, or neither?
- Did you look inside the cavity?
What are the typical next steps?
- Split any quote into ties and insulation.
- Do not extract a cavity on a hunch the survey did not state.
- Ask the Energy Saving Trust’s conditions only if someone is proposing to fill, not as a repair for cracks.
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 a guarantee for cavity insulation check the ties?
Only if the guarantee says so. Most are about the fill. Read it. The survey has not.
Can insulation hide tie corrosion?
It can hide the cavity. That is a limit, not a finding that the ties have failed.