Creosote basics, and tips to prevent dangerous buildup

Creosote basics, and tips to prevent dangerous buildup

If you have a fireplace in your home, you have experienced the warm, cozy feeling of having a nice fire going on a cool day or evening. Chimneys are specifically designed to expel the by-products of the fire and keep your home safe while providing comfort and warmth. Regular maintenance is very important to make sure your chimney is in tip top shape and in no danger of starting a house fire.


When you burn wood in your fireplace, smoke, water vapor, gases, unburned wood particles, hydrocarbon, tar fog and minerals all go up into the chimney to exit the home. These particles are hot when they rise, and as they rise in the cooler chimney, condensation occurs. This causes residue known as creosote to stick to the walls of the chimney.

There are several stages of creosote in the chimney and it is important to note that each are dangerous to your home and can potentially cause a fire if the temperature of the flue rises high enough. Initially, the creosote will appear as a flaky or dusty covering on the internal walls of the chimney. Over time, this hardens and becomes what is commonly called Stage 2 creosote. At this stage the creosote may look more like tar in the chimney. It can be sticky and drippy. At Stage 3 it is hardening and becomes shinier in appearance.

Certain conditions contribute to a faster buildup of creosote in your chimney:

1. Restricting the air supply is the most common contributor to creosote build-up. If you fail to open the damper wide enough or close the glass doors, you restrict air space and do not allow the heated smoke to exit the chimney as fast as it needs to. The residue will linger in the flue and add to your creosote buildup.

2. Burning unseasoned wood also contributes to faster buildup of creosote. Unseasoned wood has a lot of moisture and it requires higher heat from the fire to burn off that initial moisture and get the fire going well. The resulting smoke is cooler and moister, creating a perfect environment for creosote creation.

3. Lastly, cooler than normal chimney temperatures will contribute to rapid creosote build- up so be especially aware during a colder than normal winter. Leaving a low fire burning during the day so the flue doesn’t cool off completely will help keep creosote formation down.

Call Chim Chimney today and let our experienced professionals come out and inspect your chimney for creosote today. We can sweep your chimney and help ensure a safe chimney season for your home.

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