Damp and moisture meters
Dot-and-dab plasterboard lines a solid wall the survey thinks is wet. Why can the room look newly decorated while the masonry behind stays damp?
The dot-and-dab lining can leave the room looking newly decorated while the solid wall behind stays damp. The board is a new face on dabs, so the masonry the survey thinks is wet is hidden behind it. Paint on the board is not the condition of that wall. The lining is a reason to be careful, not proof of rising damp. A meter on the board is only an aid, and foil-backed board can mislead a pinless meter.
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?
Dot-and-dab leaves a gap between the board and the solid wall. Moisture in the masonry, or moist air in that gap, need not show on a freshly finished surface. A room that smells of new paint can still hide a wet wall. The survey's concern attaches to the masonry, not to the decoration that covers it from view.
Taking the board's dry face as a clearance would reverse the finding. The report thinks the solid wall is wet and is telling you the lining hides it. Opening a section, if you need to see the masonry, is a further instruction. Until then do not write that the wall has dried because the room has been redecorated.
What should you ask your surveyor?
- What made you think the solid wall is wet if the board face looked new?
- Is the lining dot-and-dab, and did you see the masonry at any edge?
- Are you refusing to treat the new decoration as a dry wall?
What are the typical next steps?
- Do not take new plasterboard as evidence the solid wall behind it is dry.
- Ask where the masonry could actually be seen, if it could be seen at all.
- If the wall must be inspected, agree an opening rather than trusting the paint.
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 a skim and paint close this comment?
No. Decoration covers the board only. It does not dry the solid wall the survey thinks is wet, and it does not prove rising damp.
Will a pinless meter on the board read the masonry behind?
Not reliably. The meter is an aid on the face it meets. Foil-backed board can mislead it, and the wall sits behind the gap.