Local chimney masonry repair for Bellair-Meadowbrook Terrace homes

Stair-step cracks along the bed and head joints

Zigzag cracks that climb a chimney along the horizontal bed joints and the short vertical head joints are movement cracks. The mortar gave way along its weakest path, which is the pattern a sound wall is designed to allow. The cause can be settlement, thermal movement, or pressure from something inside the wall such as rusting steel.

Once the cause is dealt with and the movement has stopped, the cracked joints are raked out along their whole length and repointed. A crack filled from the surface without raking stays a crack behind a thin skin of new mortar, and it reopens.

Salvaged brick from the same chimney

The closest match to the brick in a chimney can be more of the same brick. When the top of a stack is relaid, sound units from the dismantled courses are cleaned of old mortar and reused. When only a few units are needed, brick can sometimes be taken from a part of the chimney that is hidden, such as inside the attic, and replaced there with a new unit where color does not matter. Salvaged brick has already weathered with the rest of the stack, so it blends in sooner than new brick does. Salvaged units are checked for cracks and soft faces before they are reused.

White deposits as a map of the water

White deposits on chimney brick are salts carried out by water as it dries at the surface. BIA's efflorescence note explains that it takes three things together: soluble salts, water in contact with them long enough to dissolve them, and a path through the masonry to the surface. Because the deposit appears where water leaves the wall, its pattern shows where water has traveled.

A band under the crown, streaks below a shoulder, or a patch on one face each point to a different entry point. We read that map before planning the repair. The deposit itself can be brushed off dry once the water that carried it has been stopped.