Chimney masonry is highly vulnerable to moisture, and a serious problem that often results from moisture intrusion is spalling. Spalling means the surface of bricks break and pop off. By keeping up with annual chimney inspections, your chimney technician can spot warning signs and could help prevent spalling. The worst-case scenario is for spalling to be ignored. Learn more about each of these issues below.
The cause of spalling is moisture in the masonry. Many features of chimney exteriors are there for the purpose of protecting the masonry from the damaging effects of moisture. When a chimney is built, the exterior portion on the roof may start out well-protected. Over time, however, components of the chimney end up failing, which allows moisture into the bricks.
For example, the mortar forms a seal that protects masonry. When the mortar deteriorates, repair is needed. If caught in time, no major damage will have been done. In that case, a procedure called “tuckpointing” can be used. Old mortar is removed and fresh mortar is added during the tuckpointing process. Once the job is complete, the chimney has renewed structural soundness and usually looks as good as new.

What Causes Spalling?
