When it comes to keeping your fireplace and chimney clean, most homeowners understand the importance of removing soot and ash. However, there may be something more dangerous hiding in your flue – creosote.
What is creosote? 
Creosote is a naturally occurring byproduct of combustion. All fuel burning fires create creosote during the combustion process, including wood, pellets, natural gas, coal, and propane; however, creosote creation is the most common and most prevalent in wood burning fires.
There are three stages of creosote. The longer the creosote is allowed to remain in the flue the more advanced the stage will become.
- Stage 1: Light and fluffy like powder or soot. In this state, creosote is easily removed during a chimney sweeping.
- Stage 2: Shiny, hard, black flakes. This requires the use of tools such as drills or rotary loops to remove.
- Stage 3: Thick, hardened tar. Also known as glazed creosote, Stage 3 creosote is extremely difficult to remove and can damage the flue liner.
Why is creosote dangerous?
Creosote is dangerous because it damages your flue in two ways. First, because creosote is highly flammable it can accidentally ignite due to stray sparks or embers from the fire. Accidental creosote ignition is responsible for more than 25,000 chimney fires in the United States each year.
The second way that creosote damages your chimney system is by eroding and damaging the chimney flue liner. The longer creosote remains in the flue the more difficult it is to remove; removing stage 3 creosote, for example, often causes damage to the chimney flue liner underneath. Likewise, excessive creosote buildup can also cause smoky chimney odors throughout the home.
Preventing Creosote
As a naturally occurring byproduct of combustion, it is impossible to entirely prevent creosote buildup. However, there are a number of ways that homeowners can minimize creosote creation when using the fireplace.
- Use the right firewood. Burning seasoned hard woods creates the least amount of creosote. Freshly cut, green, or wet wood creates more creosote as it burns due to the high moisture content and lower burn temperature.
- Stop smoldering fires. Fires allowed to smolder or burn at a low temperature for a long period of time can create additional creosote. This is especially important for wood stove owners; purposefully maintaining a low temperature in the stove can create excessive creosote in the flue.
- Resize the flue. If you have changed fuel sources or installed a new insert, the flue may need to be resized. A correctly sized flue ensures that too must cold air is not pulled down; this can prematurely cool the creosote and cause it to harden faster.
There may be more in your chimney than just soot and ash. To prevent harmful creosote from negatively affecting your chimney system it is important to have it professionally swept at least once per year. For more information about the dangers of creosote or to schedule your next chimney sweeping contact the experts at Coopertown Services today.