Roofs and flat roofs
A downpipe from the main roof dumps onto a lower flat roof with no shoe. What has the survey not flow-tested about that lower covering?
The survey has not flow-tested the lower covering at all. It saw a downpipe from the main roof dumping onto the flat roof with no shoe, which is a concentrated discharge onto one spot. It has not tested how much water arrives, whether the lower felt or membrane copes with that point load, how the falls take it, or whether the lower outlet clears it. No shoe means the water is not turned and spread. The finding is that discharge detail. It is not a drainage test, and it is not a verdict that the lower covering has failed.
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 shoe, or a proper outlet onto a gutter, turns the downpipe so water does not hammer one patch of flat roof. Without it, the upper roof's rain lands in a jet. That can scour felt, pond if the fall is poor, and overload a small outlet. Seeing the pipe end is not the same as running water through both roofs. The survey recorded the dump point it could see. The behaviour of the lower covering under rain remains untested.
A rainwater contractor can fit a shoe or take the downpipe to a gutter, and can say whether the lower roof already shows wear at the landing spot. Tell the solicitor the report stops at an untested discharge, not at a failed flat roof. The survey has not specified a new lower covering and has not measured the flow. If the flat roof also ponds, keep that as its own note rather than assuming this pipe has already holed the membrane.
What should you ask your surveyor?
- Where on the lower roof does the downpipe land, and was a shoe missing?
- Did you see wear or a split at that landing spot, or only the open pipe?
- Was the lower outlet included in the note, or was it not tested?
What are the typical next steps?
- Treat the note as an untested discharge onto the lower roof.
- Ask a rainwater fitter to shoe the pipe or carry it to a gutter.
- Do not call the lower covering failed because the pipe dumps on it.
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 lower roof looks new, has the discharge been solved?
A new-looking covering does not change the missing shoe. The survey still has not flow-tested how that roof receives the upper downpipe. Appearance is not a test of the discharge. Asking about it again later still leaves this shoe point outside what the survey decided.
Does an internal stain under the flat roof prove this pipe is the cause?
Not by itself. A stain shows wetting was noticed. The survey did not flow-test the downpipe and has not tied that stain to the dump point as a proved path. The home survey itself did not pursue this stain question any further than the visit.