Non-standard construction

A no-fines wall has plugs that look like an injected damp-proof course. Has the survey proved that injection worked?

No. Plugs in a no-fines wall that look like an injected damp-proof course show that holes were drilled. They do not prove the injection filled the concrete or that the wall is now dry. No-fines is solid concrete, not a cavity to be treated like a 1930s cavity. The surveyor notes the plugs and any stain. They do not re-inject and they do not certify a damp treatment. This is not an empty cavity, and an empty cavity is not the finding.

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?

Injection leaves a row of filled holes. On a cavity wall those holes are aimed at a gap. On no-fines concrete there is no such gap: the wall is a solid cast without the usual coarse aggregate. Plugs copied across from cavity practice do not, by themselves, show that a cream travelled through the concrete or that rising damp has stopped. The survey can see the plugs, the plaster, salt or staining, and can use a meter only as an aid. A meter is not a proof the treatment worked, and one dry afternoon is not a history.

Do not pay for a further injection merely because plugs exist, and do not skip a damp question because plugs exist. Ask what else was seen at that wall: outside ground levels, a bridged floor, a leak, or only the holes. No-fines should not be specified as cavity insulation. An empty cavity was not identified here. If the report recommends a damp investigator, that person needs to be told the wall is thought to be no-fines and that the earlier holes are not a test certificate. The survey has not issued one.

What should you ask your surveyor?

Did you see plugs only, or any other sign of damp at this no-fines wall?
Are you treating the plugs as evidence of drilling rather than as proof the injection worked?
Have you described the wall as solid no-fines rather than as a cavity?

What are the typical next steps?

Do not commission another injection on the plugs alone.
Do not call the wall dry because the holes are filled.
If damp is still suspected, instruct someone who will diagnose the concrete wall, not a cavity.

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

Are the plugs themselves a defect?

Not automatically. They show someone drilled the wall. The survey has not proved the treatment worked or that it damaged the concrete.

Can this no-fines wall be filled like an empty cavity?

No. It is solid concrete. An empty cavity is not what was seen, and an empty cavity would not itself be a defect anyway.