Chimney stack repairs

Repointing: raking out mortar joints that have crumbled and filling them again
Flaunching: renewing the sloped mortar bed around the pots at the top of the stack, which throws rain off
Pots and cowls: resetting loose pots and fitting cowls or caps
Rebuilding the top courses of a stack where the bricks have come loose

Lead flashing

Lead is used wherever a roof meets something that is not roof: the side of a chimney, a wall, the cheek of a dormer. Step flashings are tucked into the brickwork and lapped over the tiles, so water running down the wall is turned out onto the roof.

When the mortar holding a flashing lets go, or the lead itself splits, water gets into the roof at that point. Damp on a chimney breast or in the ceiling beside it is the usual sign.

Chimneys on listed homes

If your home is listed, check before work on the chimney starts. Historic England's guidance is that like-for-like repair may not need listed building consent, but where there is doubt it is worth checking with the council first.