Repairing the Brick Stacks on Murray Houses

Below the roof line a chimney is braced by the house around it and sheltered from rain. Above it, the same brickwork is a free-standing column exposed on four sides. That is where Murray chimneys deteriorate, and it is why almost every repair we quote here is measured from the roof up.

Slender stacks and what holds them together

Post-war chimneys in this part of the valley are frequently slim, built one brick thick around the flue tile. There is not much material there, so there is not much margin. When the mortar joints erode and the crown cracks, water reaches the flue tile, freezes, and starts breaking the tile as well as the brick. Since the tile contributes stiffness to a slender stack, that is a compounding problem rather than a cosmetic one. A stack you can rock by hand has gone past repointing.

The abandoned chimney nobody maintains

Plenty of chimneys in Murray no longer vent anything. A coal or oil furnace was replaced generations ago, the fireplace was closed off, and the brick above the roof has simply been left. Nobody notices deterioration on a chimney they have no reason to think about, which is how abandoned stacks end up as the most damaged masonry on an otherwise well-kept house. If yours serves nothing, the honest options are to maintain it properly, or to take it down below the roof line and patch the roof over it. What it should not do is stand there shedding brick.

Mortar strength is not a virtue

The instinct with old masonry is to repoint with the strongest mix available. That is backwards. Older brick is comparatively soft, and mortar harder than the brick transfers stress into the brick face instead of absorbing it, so the units spall while the joints stay perfect. Matching the existing mortar in strength and composition is the difference between a repointing job that lasts thirty years and one that damages the wall.

What repair usually looks like

Rake out and repoint the failed joints, replace spalled brick with matched units, cast a new crown with a proper overhang and a drip edge, and correct flashing that was caulked rather than let into a joint. Where the stack has lost too much section, rebuild from the roof line using the sound brick below as the base. We will show you photographs of why we are recommending one rather than the other.