Question answered
Chimney breast removed but the stack left: is that safe?
The short answer
It can be safe, but only if the stack above was properly supported when the breast came out. The breast carries part of the building's load, and the Planning Portal says Building Regulations approval will always apply when removing one. A stack left without proper support can be a hazard in a gale. If you are unsure what was done, have it looked at before you assume it is sound.
Taking out a chimney breast opens up a room. If the stack above was left in place, the question is what is now holding it up, and whether anyone checked.
What the breast was doing for the stack
A chimney breast is the brick or stone mass that projects into a room and carries the flues up through the house. Above the roof line it becomes the stack. The whole thing is one column of masonry, and the weight of the stack and the pots sits on the breast, which in turn bears down on the floor or wall beneath it.
When the breast is removed on the upper floors, that column is cut. Something has to take the load that the breast used to carry. In the usual method the brickwork above is held up with a supporting beam or steel angles, often with gallows brackets, a pair of projecting steel supports built into the wall that carry the remaining masonry above.
If those supports were never fitted, were undersized, or have been loaded unevenly, the stack above is relying on bricks that were never built to span a gap. It may look fine for years and still be carrying a risk.
Building Regulations always apply
The Planning Portal states that "Building regulations approval will always apply when removing chimney breasts as they are part of the building's structure." It adds that taking out the stack itself may be treated differently. So removing a breast is never a job you can do without approval, whatever the size of the room or the house.
Approval means a building control body looks at the proposal, and the inspector checks the support work at the right stages. It is worth confirming what was done in your case. If you bought a house where the breast has gone, ask the seller for the paperwork, or ask the Adur & Worthing building control team whether an application was recorded. Do not assume it was.
Where the chimney is on a party wall, the neighbour's side matters too. Under the GOV.UK party wall guidance, "removing chimneys from a party wall" counts as notifiable work, and the neighbour must be told between 2 months and a year ahead.
Signs that the stack is not properly held
Some warning signs can be seen from outside. A stack that leans, or has changed angle over time, may be moving on a poor support. Cracks in the brickwork that run diagonally, or a widening gap where the stack meets the roof, are signs of movement. In the room below, the ceiling and wall near where the breast stood may show cracking or sagging.
In the loft, look at the remaining brickwork above the ceiling line. You should find some form of support, a steel or concrete element, built into the wall on each side. If the stack seems to stand on thin air, or on a timber that was never designed to carry brick, get advice. Do not lean on the masonry or try to test it.
If you see movement, our page on leaning chimneys sets out what causes it and what happens next.
What we check, and who decides the fix
Our survey covers the stack from the roof side and from inside the loft. We note how it is carried, photograph the brickwork, supports, flashing and flaunching, and pass the pictures to you. We do not judge the structure on its own. Where the support looks inadequate or the history is unknown, we recommend a structural engineer, whose calculation and design the building control body can then approve.
The options usually run from adding or correcting the support, to reducing the height of the stack so there is less weight to carry, to taking the stack down altogether. Our page on scaffolding for chimney work explains how the stack is reached, and whether the works are notifiable is for building control to say.
Where the stack has to come down, we remove it and make the roof good with matching tiles or slates. The written quote, one total figure, comes after the survey.
Damp and weather problems after a breast comes out
A stack left with no fire or flue in use needs ventilating at the top, otherwise damp can build up inside the remaining flue and show as stains in the room below. A capped pot with a vent, or a cowl, lets air through while keeping rain out. A bird guard, covered in our bird guard page, also keeps the flue clear.
The flashing where the stack meets the roof must stay sound. Water getting in there runs down the remaining masonry and shows up on a ceiling. Treating the surface does not cure it; see chimney waterproofing for why.
The remaining stack may also have been left with open joints on the side where the breast was cut away. All of this is part of the survey. Our chimney repairs page lists the full range of work.
Breast removal: two more questions
How do I check that the breast removal in my house was signed off?
Ask the seller or your solicitor for the building control completion certificate. If there is none, contact the Adur & Worthing building control team to ask what is on record. A structural engineer can then advise on whether the support in place is adequate.
Can the stack just be taken down once the breast is gone?
Often it can, and that removes the weight altogether. The rules can differ from those for the breast, so check with building control before you plan it. The roof must then be made good, and a party wall notice may apply if the stack is shared.
Tell us about your roof
Describe what is happening and we will call you back to arrange a visit.
- Photographs of what we find
- A written quote with one total price
- Or call 01903 299063
10-year workmanship guarantee, in writing.