Creosote is a gummy, foul smelling, corrosive, and extremely combustible substance that if no precautions are taken will coat the inside of everything that it passes through. By definition creosote is simply unburned wood particles and condensed flue gases which deposit on the inside of your chimney.
I am Melissa from Northline Express and I am going to introduce you to creosote as well as its dangers. A creosote buildup forms in your chimney as the flue gases exit the fireplace or wood stove and draft upwards into the relatively cold flue where condensation occurs and begins to solidify. This results in a carbon based condensation that materializes inside the flue and becomes creosote.
As a creosote buildup forms on the chimneys interior it goes through stages becoming more and more of a hazard as it goes through each stage. All stages of creosote can exist in one chimney and no matter if you have one or all three of the stages it is going to be highly combustible. If it is allowed to build up in sufficient quantities and ignite inside the chimney flue the result is a volcanic chimney fire the can eliminate or really damage your home in just a matter of minutes.
Creosote buildup is also pretty sneaky. You may not even notice it at first but it tend s to feed on itself. As it builds up it is going to restrict the flow of the chimney or stovepipe causing the smoke to slow down on its way out of the chimney. This allows more time for that smoke to cool forming more creosote thus further restricting the flow of your chimney, causing the cycle to continue and worsen. If you are not addressing the creosote buildup it can quickly build to a point where it is dangerous to even do so.
A chimney fire will occur when built up creosote deposits are ignited by extreme heat from the fireplace or wood stove. For this to occur it does require that the creosote be subjected to high temperatures of over 1000 degrees or so. Though 1000 or more degrees does seem a bit extreme the following quote from the March 1990 Home and Hearth Magazine puts it into a good perspective, “Creosote buildup by itself or in combination with other factors was involved in 92% of chimney fires reported in a study commissioned by the Wood Heating Alliance.” A creosote buildup of as little as 1/8” to ¼” is sufficient to create a fire hazard.
The best way to prevent creosote buildup in your chimney is just that, Prevention. The wood that you burn has a lot to do with the amount of creosote that you are going to see in your chimney. All firewood contains water to some degree but how much it contains is what is important. All of the water contained in the wood as you burn it is going to turn into steam as the wood burns. That steam will then enter your chimney at temperatures around 212 degrees F. The steam will be considerably cooler than the condensation point of creosote gases which is 250 degrees F. As that steam enters your chimney is going to cool the chimney, those gases are going to condense, and that is how creosote is formed. This is true whether you burn hardwoods or softwoods. The moisture content is really all that matters. It is important that when you choose your firewood you check your firewood, before you start burning it, to ensure that the moisture content is between 15-20% for optimal burning.
Another way to prevent creosote buildup is to keep the chimneys temperature above 250 degrees Fahrenheit all the way up. The warmer the walls of the chimney the less the creosote can adhere to them. The temperature of your stack is also affected by the size and location of the chimney. If the chimney is on an exterior wall as opposed to an interior wall it will constantly be subject to outside cooling effects. If the chimney is over sized it is also going to require more heat to keep those surface walls warm due to the increased mass. With this thought in mind you can see how a very large chimney that was never really warmed up would have the potential to have excessive creosote deposits.
Burning wood whether in a fireplace or a wood burning appliance offers many advantages to the homeowner including the allure of heating with wood, the joys of stoking the fireplace, and tending to the demands of your fire. By taking a couple of steps to keep your fireplace clean from creosote buildup you will enjoy all of the benefits of natural wood fires without the risks of an unnecessary chimney fire.
I hope that you found this information from NorthlineExpress.com helpful, keep watching our series on creosote. Next, I will be covering the different stages of creosote buildup and what products we recommend to help eliminate that in your chimney.