Roofs and flat roofs
A secret gutter behind a parapet could not be reached. Which overflow path is untested?
The overflow path from the secret gutter is untested. A secret gutter behind a parapet could not be reached, so the channel, the outlet and the route water would take if that outlet blocked were not seen working. Secret gutters sit out of ordinary view, between a roof slope and a wall or parapet, and they fail quietly until water comes over a weak point into the building. The survey recorded that it could not get there. It has not decided that an overflow works, or where water would go if the gutter fills.
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?
When a secret gutter blocks, water does not always announce itself at a downpipe you can see from the garden. It can spill into the parapet, into the top of the wall, or back under the roof covering, and those paths stay hidden until staining appears indoors. Because the gutter was not reached, none of those routes was watched with water in the channel. The surveyor has not lifted the covering and has not claimed a clear outlet. The untested path is the overflow from that unseen gutter.
Ask a roofing contractor to reach the gutter, clear it if that is agreed, and photograph the outlet and any overflow point, as work beyond this survey. Tell your solicitor the secret gutter is an access limit, not a clean bill. Do not tell a lender the parapet drainage is sound because the elevation looked even. The report's point is that the overflow path was never tested.
What should you ask your surveyor?
- Was the secret gutter reached, or only noted as inaccessible?
- Which way would water leave if the outlet were blocked?
- Has any indoor stain been tied to that gutter by a water test?
What are the typical next steps?
- Treat the secret-gutter overflow path as untested.
- Ask a roofer to reach the gutter and photograph the outlet.
- Do not describe the parapet drainage as sound.
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
Does a dry ceiling today prove the gutter can overflow safely?
No. A dry ceiling shows no active stain at the visit. It does not show the overflow path, because the gutter was not reached and was not tested. A secret gutter can be blocked and still leave the rooms dry until the next heavy rain. Do not convert a dry day into a proved overflow.
Can binoculars from the garden replace getting into the gutter?
They can show a parapet from afar, and sometimes a glint of metal. They cannot show the outlet throat, the debris in it, or the path water takes when the channel fills. The survey already records that the gutter could not be reached. A distant look does not close that limit or test the overflow.