Roofs and flat roofs
The secret gutter's only outlet is a small hopper that is blocked. Why is the hopper the first defect, rather than the tiles in front of the gutter?
The hopper is the first defect because it is the secret gutter's only outlet and it is blocked. Water in that gutter has nowhere else to go. The tiles in front of the gutter are the covering you see first, and they are the wrong place to start if the outlet cannot empty. The survey has seen a blocked hopper serving as the sole outlet. It has not blamed the tiles, has not stripped them, and has not decided they are sound. A blocked only-outlet will back the gutter up whether the tiles in front are neat or not.
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 sits behind a parapet or a cornice, out of the casual view, and it lives or dies by a small outlet into a hopper. If that hopper is choked with leaves or silt, the gutter fills and water goes over the back or into the wall. Tiles in front can be slipped, mossy or perfect, and they are still not the discharge. Starting with the tiles spends attention on the slope while the only way out of the gutter is shut.
Clear the hopper, or have a roofer clear it, and see whether the secret gutter then drains, before anyone is asked to reline the slope in front. Tell the solicitor the first defect is the blocked only-outlet. If, after the hopper runs, the tiles still let water past, that is a second note. It is not the note the survey has put first. The inspection did not water-test the tiles and did not need to in order to see a blocked hopper.
What should you ask your surveyor?
- Is the hopper the only outlet from the secret gutter?
- What is blocking it, as far as you could see?
- Are the tiles in front a separate note rather than the first cause?
What are the typical next steps?
- Treat the blocked hopper as the first defect.
- Do not start with the tiles in front of the gutter.
- Clear the only outlet before you commission work to those tiles.
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 tiles are mossy, should they be ranked first after all?
No. Moss on the tiles is a covering condition. The secret gutter still has only one outlet, and that hopper is blocked. The survey has not moved the tiles ahead of the outlet that stops the gutter emptying. The blocked hopper is still the only way out of that gutter.
Once the hopper is clear, has the survey certified the gutter?
No. Clearing it would remove the blockage the survey saw. It would not be this inspection certifying the secret gutter, the sump or the tiles. The report's point is why the hopper comes first, not a later guarantee. A later clearance would be new work, not this report's certificate.