Chimneys & leadwork

A tile sheds water. A joint has to be made to shed water, and the material we make joints with is lead — because it moves with temperature, it dresses to any shape, and it lasts the better part of a century when it is cut to the right code and lapped properly. Almost every leak we chase in Boldmere and the Sutton terraces ends up at a joint: a chimney stack, an abutment, a valley, or a bay roof.

The enemy is the cement fillet. Somewhere along the line it became normal to seal a chimney to a roof with a triangular smear of sand and cement instead of lead soakers and stepped flashing chased into the mortar joints. Cement and brick expand at different rates, so it cracks. Once it cracks it holds water against the stack rather than shedding it. Then someone smears more cement over the crack. We take a lot of those off and do it properly — individual soakers between each course of tiles, a stepped flashing let into the brickwork, wedged and pointed, and a proper back gutter behind the stack.

On the brickwork itself, the questions are repointing, rebuilding above the roofline, or removing the stack entirely. A stack takes weather from every side and it is the most exposed masonry on your house, so it degrades faster than the walls below. Where it is only pointing, we repoint in a mix appropriate to the brick — a hard modern cement mortar on soft Victorian brick will destroy the brick faces over a couple of decades, which is a favour nobody needed. Where the stack is genuinely gone above the roofline, we rebuild it, reusing the original brick where it is sound.

Shared stacks on the Boldmere and Sutton terraces need one extra conversation, which is with next door. The stack sits on the party wall and the work affects both houses. We are happy to talk to your neighbour and we would rather do that at the start than halfway up a scaffold.