Age and type of house
A shop extractor passes through the wall under the flat and the brick around it is stained. What grease and weather path is that hole, separate from the flat's own roof?
The hole where the shop extractor passes through the wall is a grease and weather path of its own, separate from the flat's roof. The duct goes through the brick under the flat, and the staining around it can be fat, condensate or rain at that penetration. The survey can see the hole and the stained brick. It has not traced a leak from the flat's covering, and it has not tested the extractor. The path to name is the opening in the wall, not the roof over the flat.
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 shop fan pushes greasy air through a duct. Where that duct punches the wall, the joint has to keep rain out and keep condensate from running back into the brick. A stained ring around the opening fits that joint. It does not require a hole in the flat's roof. The two paths meet only if someone traces water from the roof down to this brick, which the survey has not done. Keep the extractor penetration as its own defect.
The duct is likely the shop's installation. Ask the solicitor which demise must maintain the hole, the shop or the flat above, because the survey cannot allocate it from stained brick. A builder can remake the flashing at the duct. Do not accept a roof repair to the flat as the answer unless water is actually being traced from that roof. The inspection has not made that trace.
What should you ask your surveyor?
- Where does the shop duct pass through the wall, and what staining surrounds it?
- Did you trace any of that staining to the flat's roof?
- Was the extractor itself tested, or only the hole recorded?
What are the typical next steps?
- Describe the extractor hole as its own grease and weather path.
- Do not merge that stain into the flat's roof.
- Ask the solicitor which demise must maintain the duct.
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 stain feels greasy, does that separate it from a roof leak?
Grease points to cooking extract rather than to rain off a roof covering. It supports keeping this hole as its own path. The survey has not analysed the stain in a laboratory. A greasy ring around a shop duct is still not, by itself, a defect in the flat's roof.
Is the extractor the shop's kit rather than part of the flat?
It serves the shop, and the duct happens to cross structure under the flat. Who must repair it is a lease question the survey has not answered. The condition note is the stained opening. The ownership of the fan is for the solicitor.