Like a sentry standing guard in a watchtower, the masonry chimney rises above the building roof with the best site-lines of the property. When they're in good shape and doing their job, chimneys go unnoticed. But signs of wear can be visually obvious and signal the need for a checkup. Neglect is not only detrimental to the building itself, but can also be hazardous to the occupants.
Although masonry chimneys are still being built today, they have largely been replaced by the more economical manufactured systems that utilize insulated metal vent pipe instead. The masonry fireplace/chimney embodies an architectural strength and stability that enhances building design. However, the cost of a brick-by-brick labor-intensive process is prohibitive for the average homebuilder. Even though they are slowly becoming extinct, there are still millions of masonry chimneys across America servicing the inhabitants within, and all of them will require maintenance.
A chimney's main function, regardless of the type, is to remove unwanted gases from the structure. In order to do this, it has to be in contact with both the interior (where the spent fuel is created) and exterior (where the fumes are expelled) of the building envelope. This means the masonry is subject to a lot of temperature swings and adjacent material movement; two factors that can cause grief to a building's structure. In addition to the climate temperature change, the warm gas traveling through the inner chamber can also cause decay to both the brick and mortar.
In the accompanying slide show, a chimney goes through a partial restoration process. You'll see the signs that a chimney reveals when it needs help, and how the masonry process is properly accomplished. For more information about masonry, visit the Mason Contractors Association of America.