The cottages along the village street have tall brick stacks, and over two or three centuries those stacks take a lot of weather. The brick may be soft, the mortar lime, and the flashings added or replaced several times by whoever last climbed up.
Q2.1When will repointing and repair do?
Where the stack stands upright and the bricks are healthy, raking out and repointing with a softer, lime-based mortar normally cures the leak. Cement mortar is too hard for old brick and pulls the face off, so the mix matters. New lead flashings and a fresh cap or flaunching, the mortar slope that sheds water off the top, finish the job.
Q2.2When does a stack need rebuilding?
A stack that leans, bulges or sheds brick has outlived repair. It comes down to a safe level and is rebuilt, reusing the original bricks wherever they are sound so the pattern survives. Typical national figures from MyBuilder, updated 21 August 2026, put a stack rebuild at £2,000 to £10,000 or more, which is why we explain exactly what has failed before quoting.
Q2.3What about flues that are no longer used?
Many cottage chimneys serve fires that are no longer lit. A capped flue still needs ventilation, or damp collects inside the stack and attacks the brick from within. Taking out a chimney breast inside the house always needs Building Regulations approval, and where the wall is shared a party wall notice must go to the neighbour as well.
Lead work on a cottage stack follows a simple order: the old flashing is cut out, the joint is raked, and new lead goes in and is dressed to the brick. Done well, it outlasts the repointing around it. Done in a hurry with sealant, it fails by the next winter.
See also our roof repairs page for how we trace a leak that starts at a stack. A picture of the stack taken from a safe spot in the garden is a useful first step, and it lets us arrive knowing what to look at.