Damp and moisture meters
A grid of injection plugs is in a wall that is still salting. Does the grid prove the injection worked?
The grid of injection plugs does not prove the injection worked. The plugs show that someone drilled the wall and attempted a treatment. The wall is still salting, and salts are a reason to investigate, not proof of rising damp and not proof the treatment succeeded. A moisture meter is only an aid. Until the salts are understood, the grid is the history of a job, not a clearance of the wall.
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?
Holes in a line are often offered as a damp-proof course. The holes do not show whether any fluid spread, whether it remains, or whether the damp had another cause entirely. Salts can sit in plaster after a wall has changed, and they can also mark a problem that was never rising damp. The survey records the plugs and the salts. It does not join them into a success.
Pointing at the plugs as if they closed the question hides what is still on the wall. Ask which areas are still salt-affected, and whether the ground, the plaster or a leak fits the pattern better. Do not tell a lender the wall is dry because a grid of plugs can be seen. The salts mean the investigation is not finished.
What should you ask your surveyor?
- Where are the injection plugs, and where is the wall still salting?
- Did you see a tide mark or a bridged course, or only the plugs and the salts?
- Are you refusing to treat the plug grid as proof the injection worked?
What are the typical next steps?
- Treat the plugs as a past attempt at injection, not as a successful one.
- Keep the salts as a reason to investigate, not as proof of rising damp.
- Do not decorate over the salts and then call the wall cleared.
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
If the plugs form a straight line, was a damp-proof course made?
The line only shows where the holes were drilled. It does not show a continuous barrier, and it does not show that any barrier is working.
Can old salts be ignored once the plugs have been there for years?
No. Salts still visible are a present observation. The age of the plugs does not turn that staining into a clearance of the wall.