Anatomy of your Chimney

Fireplaces continue to be beautiful additions to many homes. Additionally, many homeowners find that they rely on them in winter to add warmth and comfort to their homes.

Despite their popularity and widespread use, most people do not understand how their chimneys work. This can sometimes lead to homeowners misidentifying the cause of an issue or not realizing it is time for maintenance.

The following are some of the most important components of your chimney that many people are unfamiliar with. Learning more about the anatomy of your chimney can help you identify and understand any chimney issues you may have in the future.

Chimney cap

The chimney cap covers the top entrance of your flue, allowing smoke to safely exit while preventing water, animals, and debris from getting in. Uncapped chimneys or those with damaged caps are more likely to have issues with water damage, blockages, or animals nesting in the chimney.

Chimney crown

A chimney crown is a slab, typically made of concrete, which protects the masonry of your chimney. Damaged chimney crowns may allow water into the chimney structure or allow the masonry of the chimney to receive water damage.

Chimney chase cover

Similar to a chimney crown, a chimney chase cover protects the top of the chimney. Typically made of metal, chase covers were used regularly in the 1970s and 1980s with factory built or prefabricated chimneys. Over time, chimney chase covers may deteriorate, causing rust stains on the masonry of the chimney.

Chimney damper

The chimney damper separates the firebox from the flue. Open and closed using a pulley or a lever, the damper prevents heated or air conditioned air from escaping as well as minimizing drafts. Likewise, dampers help prevent moisture, debris, or animals from getting into the firebox. While dampers should be closed when the fireplace is not in use, the damper should always be opened before starting a fire to prevent smoke from backing up into a room.

Chimney flue

The chimney flue is the chamber through which smoke, gas, and other byproducts of combustion are vented to the outside.

Chimney flue lining

Chimney flue liners protect the surrounding building materials from the hot air, smoke, gas, and other byproducts of combustion that are travelling up the flue. There are three main types of flue linings: clay tiles, metal, or cast in place. Over time, creosote can build up on the flue lining. This byproduct of combustion is highly flammable, and it’s removal is the primary purpose of annual chimney sweepings.

Smoke chamber

The smoke chamber is designed to help compress smoke from the firebox into the flue without creating a backdraft. Smoke chambers are created with a sloping wall just above the firebox. A well designed smoke chamber with allow smoke, gas, and other byproducts of combustion to smoothly and quickly travel up the flue.

Smoke shelf

Located behind the damper, the smoke shelf is designed to catch any water or debris that enters the chimney. The smoke shelf also helps compress the large amounts of smoke created in the firebox to the much smaller entrance to the flue.

Chimneys are complex structures with a number of working parts that must be kept up in order to keep your fireplace working well. Contact the experts at Jack Pixley Sweeps today to schedule a sweeping and inspection to ensure your fireplace and chimney are in prime condition.