Parts of a Chimney
Before operating or maintaining a fireplace and chimney, it is important to know and understand the different parts of the chimney and their function in keeping your home warm and safe. Let’s start from the top down to understand all the parts of a chimney and fireplace.
- Chimney Cap – This is the very top of the chimney that keeps rain and other debris out of your home
- Chimney Crown – The entire part of the top of the chimney that usually has a cage to allow the smoke to escape, but keeps other animals out. The crown also encompasses the Chimney Cap.
- Flue – This is the main part of the chimney that the smoke rises through and out.
- Flue Lining – A lining helps keep a masonry fireplace safe and easy to clean. Materials are stainless steel or specific lining tile that ensures minimum accumulation of debris.
- Chimney Case – or walls. The structure of the chimney itself.
- Smoke Chamber – the tapered space to gently compress the escaping gas into a smaller space to prevent a backdraft.
- Smoke Shelf – the flat shelf in the back of the flue just at the damper. This shelf catches any debris that might fall down the flue and helps with large volumes of smoke just before the smoke chamber.
- Damper – the flap that can be opened or closed from the inside for use or non-use of the chimney. Closing can help keep out debris as well as loss of energy inside the home.
The other parts of a fireplace, they include:
- Throat – small opening before the damper for smoke to rise.
- Lintel – The piece just above the firebox opening for structure and support.
- Firebrick – the lining of the firebox that can withstand high temperatures.
- Inner Hearth – The surface within the firebox where the fire takes place. Inner hearth tiles can also can withstand high temperatures.
- Outer Hearth – The structure that is just outside the firebox. Material must be heat resistant.
- Mantle – shelf on the outer hearth for decorative purposes. In older fireplace designs, it helped catch smoke, but with modern designs serve no primary function.
- Foundation – the lowest portion of the chimney walls. It serves to support the chimney itself.
The three most important areas to always check for a healthy fireplace is the foundation, the firebox, and the flue and/or flue lining.
Over time with excessive heat and freeze/thaw cycles, masonry can shift and crack and have support issues with chimneys. Cracks in the foundation need to be checked and addressed immediately.
It only takes one hot fire to crack the firebrick in the firebox. Excessive soot in the firebox can also compromise the firebricks job of dissipating heat and can crack. Cracks in the firebrick expose the structure masonry to excessive heat that can cause structural cracks may also cause smoke to travel in other areas of the house.
Excessive soot in the flue and/or flue lining compromises the flue of doing its job of keeping the smoke out of your house. Soot is also highly flammable and can cause a fire within the flue if too hot.
Always have your chimney inspected yearly and ensure it is clean and maintained properly for years of enjoyment, safety, and warmth.