I wrote a post last month titled Anatomy of a Chimney – How to Choose the Best Chimney Cap, so today I’d like to dive more deeply into the actual anatomy of your chimney and fireplace, explaining what each area does. I believe that knowledge is power, and by sharing this knowledge I’m shifting that power to you. All homeowners need to know and fully understand how their fireplace and chimney work so they can more easily see when potential problems arise.
Chimney Cap: If you read my previous post about the anatomy of a chimney, you know what the chimney cap does and how to choose the best one for your needs. As a recap: the chimney cap is mounted on top of the chimney. It generally has a flared top to help whisk water away from the flue opening and a mesh screen around it to prevent small animals, birds, and debris from entering the chimney.
Mortar Crown: The mortar crown is the cement area just above the brick or masonry, but below the chimney cap. The crown’s job is to drain water away from the flue. This is ideally the second line of defense against water damage to your chimney structure.
Smoke Chamber: The smoke chamber is located just above the smoke shelf and the damper. This is where the smoke gathers before rising into the flue, and out the top of the chimney.
Damper: The damper controls how much smoke and heat escape through the chimney. It is adjusted as needed by a latch, pull chain, or handle. Open it for more air flow; close it slightly for less flow. The damper should always be closed during the summer when it is not in use.
Lintel: The lintel is the support for the chimney structure. It should be concrete, slate, granite, or some other noncombustible substance.
Firebox: Exactly as the name suggests, the firebox is where you build the fire.
Hearth: The hearth is where the part that extends from the firebox to the “step” in front of the fireplace. The metal grate sits partly on the back of the hearth.
Ash Dump: The ash dump is located below the metal grate that you build your fire on. This is where the ashes fall while the fire is burning. There is usually an access door for easy ash removal from the ash dump.
Foundation: The foundation is the noncombustible seat that supports the entire structure.
Any Questions?
That is a quick rundown of the full anatomy of your fireplace and chimney structure. If you have any questions or would like a more detailed explanation please leave a comment below. Remember to schedule your annual chimney cleaning and inspection before you build the first fire of the season.