By Ashley Eldridge
Director of Education The Chimney Safety Institute of America( CSIA)
Dead in the Water:
Proper Care and Maintenance of Chimneys
I n a hypothetical list of the most taken-for-granted parts of an apartment community, it’ s a guarantee that chimneys are at or near the top.
Chimneys tend to receive neither the attention nor the concern usually accorded other service systems. It’ s a safe assumption that because a chimney tends to perform its function reasonably well— even when abused or neglected— this atmosphere of indifference persists.
Chimneys are far from the passive black holes that most assume. They perform several vital functions, and their simple appearance misrepresents their complex construction and performance requirements. A chimney deteriorated by constant exposure to weather can be a potential safety hazard. Weather-damaged lining systems, flue obstructions and loose masonry materials all present a threat to residents. Regular chimney maintenance is essential to address damage, deterioration and future high-cost repairs.
Masonry and Water Don’ t Mix
A masonry chimney is constructed with mortar and of a variety of materials, including brick, concrete, concrete block, stone, flue tile, steel and cast iron. All masonry chimneys contain combinations of, or possibly all of, these materials, most of which are adversely affected by direct contact with water or water penetration.
All masonry chimney construction materials( with the exception of stone) will suffer accelerated deterioration as a result of prolonged contact with water. Masonry materials deteriorate quickly when exposed to the freeze / thaw process, by which moisture that has penetrated the materials periodically freezes and expands, causing undue stress. Water in the chimney also causes rust in steel and cast iron, weakening or destroying the metal parts.
With regard to stone, although most types are unaffected by water penetration, large amounts of mortar are required to properly bond the pieces together. Therefore, a stone chimney— just like a brick chimney— should be protected from the effects of water penetration.
In addition, when water mixes with creosote in a wood-burning chimney system, it will generate a highly disagreeable odor
that can permeate a common area or individual unit. Holding Back the Waters
When it comes to water-damage prevention, chimney caps, also called“ rain covers,” are probably the most inexpensive preventive measure that one can employ to prevent water penetration and damage to the chimney. Chimney caps have long been recognized as an important chimney safety and damage prevention component. Underwriters Laboratories( UL) specifies that any chimney lining system that is to be listed to their test standard must include a chimney cap.
Chimneys have one or more large openings( flues) at the top that can collect rainwater and funnel it directly to the chimney interior. A common-sized flue has the potential to allow large amounts of rain or snow into the chimney in a single winter where freeze / thaw cycles are common.
Chimney caps also provide other benefits. A strong, well-designed cap will prevent birds and animals from entering and nesting. Caps also function as spark arrestors, preventing sparks from landing on the roof or other nearby combustible material.
A chimney cap should be easily removable to facilitate inspection and cleaning. For a long and effective service lifetime, a cap should be constructed of sturdy, durable and corrosion-resistant material such as stainless steel. Caps may be designed to cover a single flue, multiple flues, a large portion of the chimney or the entire chimney top. A full coverage chimney cap usually requires a larger initial investment; however, it is probably the best investment for long-term protection because of its ability to safeguard the entire chimney crown.
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