The short answer
In a flat, the lease decides. The stack above the roof is normally part of the building's structure, which a freeholder or management company looks after, while a flue serving only your flat or a fireplace inside it can be yours. Read the lease, ask the managing agent in writing, and agree who acts, who pays and who gives access before any work starts.
What the lease says
A leasehold flat is a right to occupy part of a building for a term of years, and the lease lists what that includes. It also lists what stays with the landlord. The roof, the main walls and the chimney stacks that rise above them are usually in the second group, because they serve the whole building.
Look for two things in the lease. The first is the demise, the description of what you hold. The second is the repairing covenants, which say who must keep each part in good order. A clause that gives the landlord the duty to repair the structure, roof and chimney stacks, with the cost shared through a service charge, is common.
The inside of the flat is generally yours. That can include the fireplace, the hearth and the flue lining up to the point where the flue meets the shared stack, but leases vary and some name the flue as shared. Do not guess from custom: read the wording.
If you own a share of the freehold, the building is likely managed by a company in which you are a member. Repairs are then decided collectively, and the cost is split in the proportions set out in the lease.
Some flats are in converted houses and have no managing agent at all. The lease is still the starting point, and a solicitor can help if the wording is unclear.
Who acts when a stack fails
If a stack is leaking, leaning or shedding brick, the first step is to tell whoever manages the building, in writing, with photographs. Say where the problem is, when you noticed it and what damage has appeared in your flat. Keep a copy.
The freeholder or agent then arranges a survey and a repair, and charges the cost through the service charge if the lease allows. That is the normal route, and it spreads the bill across the flats that benefit from the stack.
Where the flues from several flats join one stack, a defect can affect everyone. A rebuilt top section, a new cowl or new flashing helps all of them, and so the work is shared.
If the managing party does nothing, send a further letter that sets a reasonable deadline and say what you will do next. Citizens Advice can explain your options on a repair dispute, and a solicitor who specialises in leasehold law can advise on forcing action.
Avoid arranging the repair yourself without agreement, unless it is a genuine emergency such as a loose stack that could fall. Work on a shared stack without permission can lead to a dispute over who pays.
Our answer on bricks falling from a chimney explains what to do while you wait.
Agreeing the work in writing
Where a repair involves several owners or a landlord, put the agreement on paper. A short document should name the stack and the work, say who is carrying it out, state the total price and how it is split, and give the dates.
Ask the roofer for a written scope that anyone can read. It should say whether the stack is being repointed, rebuilt or capped, what happens to the flashing and the pots, and what is done with the debris. One total price is easier for a group to approve than a spread of figures.
Check the rules on shared structures. If the work cuts into a party wall, such as removing a chimney breast or a flue between two flats, the Party Wall etc. Act 1996 may apply, with two months' notice, and a party wall surveyor if the neighbour does not agree. Questions of this kind go to a surveyor and not to building control.
Our answer on who pays to repair a shared chimney stack looks at the same question for houses.
Keep every email and every quote. Disagreements over service charges often turn on the paper trail.
Access, safety and the roof
A stack is repaired from outside, so access is a practical matter as well as a legal one. The crew may need to cross a communal roof, set up a tower in a shared yard or use a flat belonging to somebody else to reach a loft hatch.
The lease usually gives the landlord a right of entry to carry out repairs, but good manners still apply. Tell the residents, say when the crew will be on site, and warn those who share the yard or the car park.
A scaffold on the pavement needs the highway authority's licence; for an Andover address that is Hampshire County Council, which expects the scaffolding company to apply. The cost forms part of the project.
Flats have no permitted development rights, so planning questions about visible changes to a stack are best checked with the council before work. Our answer on chimney repairs in a conservation area explains the position.
A block with several flats is also a place where a commercial-style plan helps: a survey, photographs, a scope and one written price, agreed by all. See the chimney repairs page for how we approach it.
