The Difference between a Chimney Crown, Chimney Chase Cover, and a Chimney Cap
While a fireplace is usually an impressive centerpiece in a home that rarely goes unnoticed, rooftop parts of the chimney may be long forgotten. In fact, it’s not unusual for homeowners to be unaware of or unsure about the functions of various rooftop components of a chimney. Three of those are a chimney crown, a chimney cap, and a chimney chase cover; and the following is a key to understanding the difference between them.
The chimney crown is the cement or masonry slab at the top of a masonry chimney. The crown is basically the seal that protects the structure from moisture, providing cover from the exterior of the masonry to the top of the flue. Being out of sight and out of mind can be a problem as regards chimney crowns because they are prone to cracking, as a result of constant exposure to the elements. With an annual chimney inspection, you can be sure your chimney crown is checked for signs of deterioration at least once per year. Either repair or rebuild is needed, once damage occurs.
A chimney chase cover is what tops chimneys built of metal, wood, or vinyl siding. It is a metal cover that fits over a chimney chase, and the purpose is to prevent water from getting into the chimney. Chase covers are the metal tops of prefabricated or factory-built chimneys. Proper installation of a chimney chase cover is essential, to ensure that water runs off. If installed incorrectly so that the chase cover is flat, water can accumulate and accelerate rusting of the cover. Galvanized sheet metal chase covers are economical but rust more quickly than covers made of stainless steel.
What is a chimney cap?
A chimney cap is an essential accessory that should be at the top of every chimney flue. Chimney caps are metal, whether made with aluminum, stainless steel, or copper. When properly installed, chimney caps keep moisture from entering the chimney flue when it rains or snows. Moisture can cause rusting of various chimney components and can cause the chimney liner to deteriorate. A chimney cap can also be installed on chimney chase covers.
A chimney cap with wire mesh provides additional benefits that can be just as valuable as keeping out moisture. The mesh will prevent animals from entering the chimney flue. In cold weather, various creatures notoriously seek relief inside chimneys, including raccoons, snakes, and birds. It’s not unusual for birds to nest in chimneys, which causes further blockage.
One more advantage of mesh is that it can act as a spark guard. Hot embers sometimes exit chimneys, and they can start rooftop fires or ignite other combustible materials. Hazardous fires are prevented by chimney cap mesh.
Chimney maintenance is important, to make sure it’s safe to use your fireplace or wood stove. If you find qualified chimney sweeps in your area and schedule annual inspections, it’ not necessary to climb on your roof and check things out. Still, knowing the difference between a chimney cap, a chimney chase cover, and chimney crown will at least familiarize you with components you need to maintain and their vulnerabilities.
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