Roofs and flat roofs
The main-roof valley of a Victorian terrace discharges onto the felted kitchen roof. Why should stains in the kitchen not be blamed on the slate slopes first?
Stains in the kitchen should not be blamed on the slate slopes first, because the main-roof valley discharges onto the felted kitchen roof. Rain from the two slate slopes is being delivered, by that valley, onto the flat felt rather than into a gutter that misses it. The kitchen ceiling is under that felted roof. The survey has seen the discharge arrangement. It has not water-tested the slates, has not decided the slates are the source, and has not proved the felt is sound. The first place to read the stains is the roof the valley is actually loading.
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 Victorian terrace often has a rear addition with a felted roof tucked under the main slopes. When the valley stops on that felt, the flat roof becomes the gutter. Slate stains, nail sickness or a slipped slate on the main slopes are real defects when they exist, but they are not the first explanation of a kitchen stain if the valley is dumping its water onto the felt above that room. The felt, the outlet and the way the valley shoe lands are the path in front of you.
Ask a roofer to look at the valley outlet and the felted kitchen roof before anyone strips the slate slopes on the strength of a ceiling mark. Tell the solicitor the survey has not blamed the slates first. Do not let a seller's note about recent slate repairs close a question about where the valley discharges. The inspection did not hose the roof, so it has not ranked every possible drip. It has ranked this arrangement as the one to read first.
What should you ask your surveyor?
- Where does the valley discharge relative to the felted kitchen roof?
- Did you see a shoe, an outlet or ponding on that felt?
- Are the kitchen stains being left unblamed on the slates until that path is understood?
What are the typical next steps?
- Read the valley's discharge onto the felt before you blame the slates.
- Ask a roofer to look at that outlet and the kitchen roof.
- Keep any slate defects as a separate note, not the first cause of the stains.
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 a few slates have slipped, must the kitchen stains be theirs?
Not first. Slipped slates are a covering note on the main slopes. The valley still discharges onto the felted kitchen roof, which sits over the stained room. The survey has not promoted the slipped slates ahead of that discharge. The felted kitchen roof is still the surface the valley is loading.
Has the survey water-tested the felt and cleared it?
No. The arrangement was seen. The felt was not hose-tested, and it has not been cleared. The point is where to look first, which is the roof the valley loads, not a certificate that the felt is sound. Seen geometry is not a water test of that felt.