Tuckpointing
Grinding out and replacing failed mortar joints in brick masonry before the brick itself starts to break down.
Tuckpointing (or repointing) is the masonry repair of grinding out crumbling mortar joints between bricks and packing in fresh mortar. On a chimney it's preventive work: mortar fails before the brick does, and once water gets behind the joints, freeze-thaw cycles spall the brick and the structure starts to lean — turning a few-hundred-dollar repair into a multi-thousand-dollar rebuild. Caught in time, tuckpointing restores both the look and the weather seal of the masonry. It shows up on most [chimney repair](/guides/chimney-repair-cost) estimates for older masonry chimneys and is worth doing the season you first notice receding or sandy mortar joints.