Chimneys and parapets
Pots on a shared stack wear cowls of different ages. Has each flue been swept?
No. Each flue has not been swept. Cowls of different ages on a shared stack are a visual note about the pots: the terminals do not match, so they were probably fitted at different times. The age of a cowl does not show that the flue below it is clear, lined, or exclusive to this house. A shared stack can serve more than one home. The survey did not sweep any flue, did not camera them, and did not test draught. Different cowls are not a sweeping certificate. Each flue remains unchecked.
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 cowl is a terminal on a pot. It can keep rain and birds out, and an older one can be cracked or blocked while a newer neighbour looks tidy. None of that is a brush down the flue. Shared stacks need care because a flue that looks as if it belongs to this house may serve the house next door. The survey sees the pots. It does not allocate flues to rooms, and it does not certify that a terminal is the right one for the appliance below.
Ask the solicitor whether any sweeping record or lining certificate is in the pack, and keep it separate from the cowl note. A chimney sweep is the person who sweeps. If an appliance uses one of these flues, that appliance still needs its own safety regime, which this visit did not carry out. Tell a lender the pots were compared by eye. Do not say the flues are clear because the cowls were counted.
What should you ask your surveyor?
- Were the flues swept, or only the cowls compared?
- Can a shared stack serve more than this house?
- Does a newer cowl prove the flue beneath it is clear?
What are the typical next steps?
- Treat each flue as unswept.
- Ask the solicitor for any sweep or lining paper.
- Do not describe mismatched cowls as a sweeping record.
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
Does a redundant pot still need a note?
Yes, if it is part of the stack the survey could see. A pot that no longer serves an appliance can still let rain in or show a failed terminal. The survey has not proved which pots are redundant. That is a question for the appliances and the papers. Different ages of cowl do not retire a flue, and they do not sweep it.
Has the survey tested whether smoke from one house enters another?
No. No flue was tested, and no smoke test was done. A shared stack makes that question possible, which is why the pots were worth noting. The visit did not light a fire or trace a smell into a neighbour's room. If that risk matters, it is a specialist look. The cowl note has not closed it.