Basements and cellars
The lightwell drain is blocked with leaves and the basement wall beside it is damp. What local path is that drain, before anyone tank the whole room?
That drain is the local path for rain falling into the lightwell, and it should be understood before anyone tanks the whole room. Leaves are blocking it, so water can stand in the well against the basement wall, which is damp beside that point. The survey has recorded the blockage and the damp wall next to it. It has not camera-surveyed the drain, has not proved the damp has no other cause, and has not specified tanking. Lining the room would cover the inside while a blocked outlet still holds water against the outside. The local path is the drain.
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 lightwell is the external area sunk beside a basement wall or window, and its drain is the outlet that should take rain away. Leaves over the grating stop that outlet, and the well can become a pond against the masonry. Damp on the inside face beside it fits water sitting there. It does not, by itself, prove that every other basement wall needs a tanking system. The survey saw leaves and a damp patch. It did not test the buried pipe beyond the grating.
Ask a drainage contractor to clear and prove the lightwell outlet before anyone prices tanking for the whole room. Tell the solicitor the survey's point is a blocked local drain and damp beside it, not a specification for a lining. The home survey has not commissioned a camera and has not watched one. Do not line the basement from this note and leave the leaves where they are. The path the survey named is the drain.
What should you ask your surveyor?
- Is the lightwell drain blocked with leaves at the outlet you saw?
- Is the basement damp beside that well rather than mapped across every wall?
- Have you left any decision to tank the room outside this report?
What are the typical next steps?
- Treat the blocked lightwell drain as the local path.
- Clear and prove that outlet before pricing tanking for the whole room.
- Do not read the damp patch as a specification for tanking.
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 leaves are lifted, has the basement damp been cured?
Not by this report. Opening the grating reopens the outlet the survey could see. It does not prove the pipe beyond is clear, and it does not prove the damp has no other cause. The survey did not camera the drain and did not specify a cure. A clear grating is the start of that local path, not a dry certificate for the room.
Could the damp beside the well be condensation instead of standing water?
It could, and the survey has not separated condensation from water held in the well. What it has recorded is a blocked lightwell drain and a damp wall beside it. That is why the drain is the local path to deal with before a whole-room lining. Tanking the basement would still not say which mechanism is at work.