Elements of a chimney stack
The visible stack includes brick or rendered masonry, mortar joints, the top flaunching and one or more pots or terminals. At roof level, flashings connect the stack to the roof covering. Each part should shed water while remaining stable in exposed conditions.
Repair scope may include
- Replacing isolated damaged bricks
- Repointing failed mortar joints
- Renewing cracked or loose flaunching
- Securing or replacing damaged pots and cowls
- Local rebuilding where masonry has become unstable
- Correcting adjacent lead flashing
Removal needs careful consideration
Removing a redundant stack may affect structure, ventilation, appearance, shared party-wall arrangements or planning constraints. Check the official Planning Portal roof guidance and obtain project-specific professional advice before alteration.
When movement is visible
A leaning, cracked or visibly unstable stack deserves prompt assessment from ground level. Keep people away from the area beneath it and do not attempt a roof inspection yourself.
Repairing the top of the stack
Upper courses, pots and flaunching receive the greatest exposure. If only this zone is loose, a controlled partial rebuild may retain the sound lower stack. The work should record the original dimensions, pot positions and brick bonding before dismantling.
Shared chimney stacks
A stack may contain flues serving more than one property. Before alteration, establish ownership and whether adjoining occupiers use a fireplace, stove or ventilation route. Structural changes or removal may also involve party-wall, planning or building-control considerations.
Completion checks
After repair, review the finished pointing, brick alignment, pot stability, flaunching falls and interface with leadwork. Photographs from the working platform create a useful maintenance record for areas that cannot be seen from the ground.
Request a stack assessment