Damp and moisture meters
A cold roof has no eaves ventilation the surveyor could see and the felt is wet underneath. What air path is missing, and what leak has that not proved?
The missing air path is eaves ventilation into the cold roof, and the wet felt has not proved a leak. A cold roof is meant to have outside air moving through the void, often entering at the eaves. The surveyor could not see that path, and the underside of the felt was wet. Wet underlay can be condensation where air cannot cross the void, or it can be rain from a fault in the covering. The survey has recorded the missing vents and the wet felt. It has not proved a leak, and it has not proved condensation.
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?
Eaves ventilation is an opening or a series of openings that lets outside air into the slope and, with a way out, lets it leave again. Without that path, moist air can linger on cold felt and wet it. That can happen with every tile still in place. It also does not rule a covering defect out. The survey could not see eaves vents. The missing path is the finding. A leak is what the wet felt has not proved.
Tell the solicitor the cold roof showed no eaves ventilation and the felt was wet, and that no leak was proved. If the void needs a designed air path, ask a roofer to consider that as a separate job. Approved Document F deals with ventilation of buildings. The home survey has not certified this roof against it and has not issued any completion paper. Do not renew the covering solely because the felt is wet, and do not add vents and call the leak question closed.
What should you ask your surveyor?
- Was eaves ventilation absent as far as you could see?
- Did the wet felt stop short of proving a roof leak?
- Which air path did you record as missing?
What are the typical next steps?
- Treat eaves ventilation as the missing air path.
- Do not read wet felt as a proved leak through the tiles.
- Ask a roofer to consider the air path separately from any covering repair.
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 one tile is cracked, has the leak now been proved?
A cracked tile is a covering defect to record if it was seen. Wet felt and missing eaves vents still do not prove that crack is the source of the water. The survey has not traced a path from tile to drip. The missing air path remains the ventilation finding. The leak, if there is one, is still unproved by wet underlay alone.
Can the felt be opened so the loft dries, and does that restore the air path?
No. Cutting the underlay is not the eaves ventilation that was missing, and the survey has not told anyone to cut it. The air path is into the cold roof from the eaves, and that path was not seen. A hole made in the felt is not a remedy this report has specified. A designed vent is a different thing.