The short answer
Like-for-like repairs such as repointing, a new pot or renewed flashings generally do not. Removing a chimney breast always does, because the breast is part of the building's structure. Taking down or rebuilding a stack falls in between, and the safe course is to ask your building control body, which in Farnborough is the Hart and Rushmoor team on 01252 398715.
Repairs that normally sit outside the regulations
Building Regulations are about new work and material alterations, such as structural changes, fire safety and energy efficiency. They are not a licence for every repair. Maintenance that puts back what was there, using similar materials, is the everyday case and normally needs no application.
For a chimney, that covers most of what roofers do at the top of a stack:
- repointing the joints in matching mortar;
- replacing a cracked pot or renewing the flaunching round its foot;
- cutting out and replacing a few damaged bricks;
- renewing lead flashings and the back gutter;
- fitting a cowl or bird guard.
These repair the stack without changing its structure or its job. The Planning Portal's re-roofing test weighs the portion of the envelope and the portion of the roof affected, and it tells the same story from the roof side. A stack repair touches a tiny fraction of either.
The qualification is that the work is truly like for like. If a repair quietly changes the way the stack carries load, or the flue's route, it is no longer just maintenance. Our survey notes the repairs that fall into this group, and the written price covers them as one job.
Chimney breast removal: always
The clearest exception is taking out a chimney breast. The Planning Portal's guidance is that approval always applies to it, since it forms part of what holds the house up. It is not a judgement call, and it does not depend on how much is removed.
The reason is what the breast does. It can carry the weight of the stack above, and sometimes it supports floors, walls or roof timbers beside it. Removing it without a proper replacement support risks the stack and the house.
That is why removal comes with structural design, usually a supporting steel in the form of a lintel or a pair of gallows brackets, and with inspection by building control or a registered approver in the same way. Our answer on gallows brackets for chimney breast removal explains the supports.
A shared breast adds a second regime. If the work cuts into a party wall, the Party Wall etc. Act 1996 may require formal notice to the neighbour two months ahead of the work, and that process is separate from building control. Party wall questions go to a party wall surveyor.
The takeaway is simple. If the job removes any part of a breast, apply for approval first and do not start until it is in place.
The in-between cases
Between plain repair and breast removal sit several jobs where the answer depends on detail.
Taking down a stack above the roof line, and capping the flue, changes the roofline and the way the flue behaves. Removing it below the roof line involves the roof structure itself, with new rafters or battens and tiling in the gap. Both need a conversation with building control, and the second is covered in our guide to removing a chimney stack below the roof line.
Rebuilding a stack is another. A like-for-like rebuild of the part above the roof, in matching brick, is closer to repair. A rebuild that changes the size, the flue or the support is closer to new work.
Fitting a liner, a stove or a new appliance involves other rules, notably those for combustion appliances, and the installer will advise. A new flue is a separate subject from roof maintenance.
A change of roof covering raises the weight question too. A covering 15 per cent or more heavier brings approval into play, and stack work done alongside a re-roof sits inside that overall picture. In these cases the safest step is to ask first.
Who to ask and what to bring
The body to ask depends on the address. In Rushmoor and Hart, building control is the shared Hart and Rushmoor team based in Rushmoor's Farnborough offices, reached on 01252 398715. Other councils have their own services, and private work can go to a registered building control approver, a regime that has operated since 6 April 2024.
When you call, have the address, a description of the work and a few photographs. Ask whether the job needs approval, what the body will want to see and how many inspections to expect. Keep any written answer with the house papers.
Compliance rests with the owner, so a roofer's say-so is not a substitute. We tell you at the survey where a job is likely to need approval, and we build the work to what the building control body asks for.
Chimney work also touches planning in protected areas, which is a separate question covered in our answer on chimney repairs in a conservation area. For the full list of repairs, see the chimney repairs hub.
