Roofs and flat roofs
A stone trough gutter holds silt. Has it been shown to discharge, or only seen full of silt?
It has only been seen full of silt. Discharge has not been shown. A stone trough gutter was recorded holding debris, and nobody ran water through it to an outlet on this visit. A full trough does not prove the outlet is open, and it does not prove the outlet is blocked. The survey can say the trough contains silt. It cannot say the gutter discharges. Clearance and a working fall remain untested.
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?
Stone troughs sit on older roofs and parapets and hold silt because they are wide and slow. Debris hides the outlet, the drip and any crack in the stone. Rain may overflow the trough into the wall below, or it may still find a hole under the silt. One dry visit cannot separate those. The mechanism is a gutter that has not been proved to carry water away. The silt is what was visible.
Ask the solicitor whether any roofing invoice or guarantee mentions this trough. A roofer can clear the silt, find the outlet and watch where water goes, including whether it spills onto masonry. The survey has not instructed that work and has not costed it. If a lender asks about the roof, say the trough was seen silted and was not shown to discharge. Do not upgrade that sentence into a test.
What should you ask your surveyor?
- Was an outlet visible under the silt or completely hidden?
- Did any staining below the trough show overflow?
- What would a water test need to show at the outlet?
What are the typical next steps?
- Tell the solicitor the trough was seen full of silt and not flow-tested.
- Have a roofer clear the silt and watch where water discharges.
- Do not describe the gutter as proved clear when you write to the lender.
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
Is a stone trough the same fitting as a plastic eaves gutter?
No. A stone trough is a built gutter, not a clip-on plastic length. It holds silt in a different way and its outlet can be a chute through a wall. The survey saw silt in the stone trough. It has not treated that detail as a modern gutter and has not run water through it.
Does silt by itself prove the wall underneath is wet?
No. Silt shows the trough is holding debris. It does not measure damp in the wall below and it does not prove rain is entering the rooms. Staining, if it was noted, is a separate observation. The survey has not moisture-tested the wall from this silt, and it has not shown that the trough discharges.