Wall ties and cavity insulation
Do drill holes in a regular grid mean the wall ties were replaced?
No. A regular grid of small holes usually means the cavity was filled with insulation, whereas replacement ties are a different operation and usually leave a different pattern of holes. The survey can describe the pattern it sees. It cannot, from the holes alone, say the ties are new or that they are 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?
Installers drill a grid so they can blow or inject fill into the void between the leaves. The holes are then filled and sometimes coloured to match. That pattern is evidence of an insulation job, not evidence of a tie survey. Tie replacement uses holes placed to reach the ties or to install new ones, and the paperwork, if it exists, will say so. A seller’s memory that “the walls were drilled” does not choose between the two. The Energy Saving Trust treats cavity fill as work you do only when the cavity and the masonry are suitable. The home survey is not that suitability test, and it is not a boroscope record of the metal.
Ask the surveyor to write “grid of filled holes, consistent with cavity fill” if that is what they saw, and not “ties replaced” unless they have a reason beyond the grid. Ask the seller for any guarantee or specification, and read whether it mentions insulation, ties, or both. A guarantee for fill does not inspect the ties on the day you buy. If there are also horizontal cracks in the bed joints, that is a separate comment and should not be folded into the drill pattern. The holes do not close that comment.
What should you ask your surveyor?
- What pattern of holes did you see, and on which elevations?
- Are you calling them fill holes, tie holes, or are you unsure?
- Did you see inside the cavity, or only the plugged surface?
What are the typical next steps?
- Ask the seller for the installation paperwork and read which trade it names.
- Do not tell a lender the ties were renewed because the brick has a grid of plugs.
- If cracks suggest tie trouble, instruct a tie inspection. Do not treat the insulation grid as that inspection.
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 one wall have both fill holes and later tie holes?
Yes. Describe both patterns if both are there. One does not cancel the other, and neither was tested by this survey.
Do filled holes mean the cavity is fully insulated?
They mean someone drilled a grid. They do not prove the fill is complete, dry, or still in place.