Generally, you don’t worry too much about the inner workings of your fireplace. You have it cleaned and inspected annually and understand the basic maintenance that comes with having a fireplace or fireplace insert. Understanding more about the anatomy of your fireplace and chimney can help you be aware of how your fireplace should function, so you’re more aware of any changes or problems. It also will help you talk to your chimney sweep about problems and understand any concerns he raises with you.

Understand your chimney type

There are two types of fireplaces and chimneys: masonry and prefabricated. Masonry fireboxes and chimneys are constructed of bricks or stones. Prefabricated fireboxes and chimneys usually are made from stainless steel. Some fireplaces do feature a hybrid design, most often combining a prefabricated fireplace with a masonry chimney. Some masonry chimneys have been relined with stainless steel. If you don’t already know what type of fireplace and chimney system you have, it may require that you take a peek up your flue to determine your chimney type.

Understand your chimney’s anatomy

The exact components of chimneys can vary. Prefabricated chimneys are built to optimize the burning and drafting of your exact model of fireplace. Masonry chimneys are more standard and more complicated. Masonry chimneys can contain up to 22 different components. Some basic chimney components include:

• The chimney throat. The chimney throat is the bottom most portion of the chimney, where smoke is first directed upward.
• The smoke shelf. The smoke shelf is a horizontal surface at the bottom of the chimney throat meant to keep debris from falling down the chimney and into your firebox.
•  The damper. The damper is a metal piece that closes off your flue when you’re not using your fireplace to keep drafts from entering your home and warm air from exiting it. It also can keep animals or debris from finding their way into your home. Before lighting a fire, you know to open your damper to allow smoke to exit your home.
• The smoke chamber. From the chimney throat, smoke travels upward to the smoke chamber. The smoke chamber is shaped like an upside down funnel to direct the smoke upwards through the chimney.
•  The chimney flue. The chimney flue is the long, hollow tube that comprises the majority of your chimney.
• The chimney crown or chase cover. The top of your chimney, it is surrounded on the outside by a chimney crown or chase cover. The crown or chase cover slopes downward and helps to direct water away from the inside of your chimney. Which you have depends on your chimney type: Masonry chimneys terminate in a masonry crown, while prefabricated chimneys are topped with metal chase covers.
•  The chimney cap. Your chimney cap is a small, metal roof-line structure that covers the opening of your chimney to prevent water from running down your flue. It usually is attached to the chimney by wire mesh that prevents debris and animals from entering the chimney and embers from exiting it.

  If you have questions about the anatomy of your fireplace or chimney, don’t be afraid to ask the experts at The Chimney Sweeper! We believe it’s an important part of our job to educate our customers about their fireplaces, stoves and chimneys.