Chapter 1: Why is the chimney on our Old Dean estate house leaking after only light rain?
What we find
The stacks on 1950s terraces and semis are often shared between neighbours and stand tall above the ridge, exposed to wind from every side. The brickwork has been weathering for seventy years, and two parts of it fail first. The mortar joints erode until rain can run into the stack itself. The flaunching, the sloping mortar fillet on top that holds the pots in place, cracks and lets water straight down the flue.
Inside, the signs are a brown stain on the chimney breast, damp wallpaper upstairs, or flaking paint on the breast in the loft. Staining that appears only after rain from one particular direction nearly always points to the stack, not the roof. Around the base, the lead flashing that seals the join between brick and tile may also have lifted or split, and that is a frequent leak on this age of house.
What we fix
We inspect the stack from a ladder or tower and photograph the joints, flaunching, pots and flashing, then repair what has actually failed. Failed mortar is raked out and repointed in a mortar that matches the brick, cracked flaunching is renewed, and loose pots are rebedded. A cowl or cap can be fitted if the flue is unused, keeping some ventilation so the chimney does not turn damp.
Where the lead has failed, we replace the flashing and the soakers, small lead tabs woven between the tile courses beside the stack. Typical UK prices reported for chimney repointing run from £450 to £1,200 and for chimney leadwork from £350 to £920; your fixed quote follows the survey. Our chimney repairs page covers the choices in more detail.