Damp and moisture meters
Does water on the inside of the glass mean the wall has rising damp?
No. Water on the room side of the glass is moisture in the air meeting a cold pane. That is condensation on the glass. It does not show that ground water is rising in the wall. A home survey can note streaming windows, mould on the glass and a lack of ventilation. It cannot turn that into a failed damp-proof course.
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?
Single glazing and cold frames do this in winter, especially in rooms that are dried, cooked in or slept in. The wall beside the window may still be dry, or it may have its own defect. The Property Care Association treats condensation as a moisture and ventilation problem. Government damp and mould guidance is about cause. Neither document says wipe the glass and inject the wall.
Trickle vents painted shut, a fan that does not run, and furniture against a cold wall are ventilation clues. They are not a survey test of the fan. There is no RICS price for new windows or a new course. If the plaster at skirting level is salty and soft, that is a separate sentence. Do not delete it because the glass was wet.
What should you ask your surveyor?
- Is the water on the glass, in the wall, or both?
- Did you see vents that were closed or painted over?
- Are you diagnosing condensation, or only noting misted glass?
What are the typical next steps?
- Wipe nothing into a diagnosis. Note where the water sat.
- Do not replace the damp-proof course because the bedroom windows stream.
- If you change the windows later, that is building work. It is not a repair the survey has specified.
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
Is water between the panes the same as water on the room side?
No. Water trapped inside a sealed unit is a failed unit seal. Water on the room face is condensation.
Does a dehumidifier on the landing prove the walls are dry?
No. It proves someone was drying air. It is not a damp survey.