Age and type of house
In a chalet bungalow the knee wall of a roof room is damp at the wall plate and the main tiles look even. What junction was not opened?
The junction at the wall plate was not opened. In this chalet bungalow the knee wall of the roof room is damp at the plate, and the main tiles look even, so the damp is sitting at the eaves junction rather than under a disturbed tile you can see from outside. The survey has recorded damp at the plate and an even covering. It has not opened the junction, has not seen the plate, the felt or the back of the knee wall, and has not decided whether the moisture is a leak at that joint or condensation on a cold line.
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?
A roof room in a chalet is built inside the slope. The knee wall meets the rafters at the wall plate, which is a crowded junction of timber, felt and plaster. Damp there can be rain getting past the eaves detail, or warm room air meeting a cold plate. Even tiles on the slope make a slipped-tile storey less likely as the first reading, because the covering you can see is orderly. They do not prove the eaves are tight.
Ask the surveyor how far the damp extends along the plate, and ask a roofer or a damp specialist to open that junction before you fund a retile of an even slope. Tell the solicitor the tiles looked even and the junction was not opened. Do not let a decorator's quote to repaint the knee wall stand as a diagnosis. Paint covers the symptom the survey already saw. It does not open the plate.
What should you ask your surveyor?
- How extensive is the damp along the wall plate?
- Did you open the knee wall or the eaves junction at all?
- Are even tiles being kept separate from the cause at the plate?
What are the typical next steps?
- Treat the wall-plate junction as unopened.
- Do not blame a disturbed tile course you did not see.
- Ask for that junction to be opened before the even slope is retiled.
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 loft felt looks dusty and dry, has the plate been cleared?
No. Dusty felt in the part of the roof you could see is not the junction behind the knee wall. That junction was not opened. Damp at the plate remains unexplained by a dry patch of felt elsewhere. The plate itself stayed behind the lining.
Does an even tile line mean the damp must be condensation?
Not yet. Even tiles make a slipped covering a weak first guess. They do not prove condensation, and they do not rule out a leak at the unopened plate. The survey has not chosen between those causes. Orderly tiles outside leave both causes open at the plate.