Roofs and flat roofs
A secret gutter behind a parapet is lined in lead that has split, and the tiles in front still look even. Where is the leak path the tiles are not showing?
The leak path the even tiles are not showing is the split lead in the secret gutter behind the parapet. Rain falling into that hidden channel can pass through the split and wet the wall or the roof build-up behind, while the front tiles stay even. The survey has recorded the split lining it could see. It has not water-tested the route or timed how long the lead has been open. It has not traced how far any wetting has travelled inside. A tidy slope in front of the parapet does not close that gutter.
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 secret gutter is a channel tucked behind a parapet, usually lined in lead, which the tiles then overlap from the front. If that lead has split, water that should run to an outlet can drop through the crack instead. The even tiles only show that the covering on the slope has not slipped. They say nothing about a lining hidden from the street. Water can reach the wall head before any stain shows on a ceiling below.
Tell the solicitor the report names a split lead gutter, not a failed tile slope, so any enquiry stays on that lining and its outlet. A roofer who works in lead can say whether the split can be repaired in place or whether a length of the gutter needs renewing. The survey has not priced that work and has not said the parapet must be rebuilt. Leave the lead as it was found until that roofer has looked. Disturbing it on a viewing can open a wider hole.
What should you ask your surveyor?
- Where along the secret gutter did you see the lead split?
- Could you see an outlet from that gutter, or only the damaged lining?
- Did any inside staining line up with the parapet, or was none recorded?
What are the typical next steps?
- Keep the finding on the split lead gutter, not on the even tiles.
- Ask a lead roofer whether the lining can be repaired without rebuilding the parapet.
- Tell the solicitor the hidden gutter is the item to enquire about.
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 an even tile line mean the parapet is dry?
No. Tiles can sit straight while the secret gutter behind them is split. The survey has not called the parapet dry, and a tidy slope is not a test of the lead lining. Any wetting at the wall head still has to be judged on its own.
If the ceiling under the parapet is clean, can the split be ignored?
A clean ceiling does not close a split in that lead gutter. Water can sit in the roof build-up or the wall head before it stains plaster. The survey recorded the lining it saw, not a pass for the rooms below.