A lot of people have heard that creosote is bad for their chimney but haven’t really taken the time to learn why—or worse, they simply don’t care. But understanding what creosote is and why it is dangerous for your chimney is incredibly important for knowing how to prevent costly and potentially life-threatening fires in your home.

What is creosote?

In layman’s terms, creosote is a tar-like buildup that attaches itself to your chimney liner or brick and occurs naturally from burning wood. More specifically, creosote is a chemical reaction of the smoke traveling up to the cold air and creating a hard substance.

As ChimneyandWildlife.com puts it, creosote is formed “when the smoke travels upward and mixes with cold air and water near the top of a chimney, it [then] solidifies and sticks to the chimney liner.”

In other words, when the smoke from your wood fire mixes with the cold air/water at the top of your chimney, you are left with a dangerous carbon-based condensation lining the chimney walls. There are three stages or degrees to the formation of creosote, each becoming increasingly dangerous.

The first stage is a dust-like particle that is easy to remove (which is why annual cleanings/inspections are so important). Then, in stage two, creosote takes the form of hardened tar which is more difficult to remove and will likely require the help of a professional.

Finally, the third stage of creosote is the most dangerous. As MyChimney.com explains, “Third-degree creosote is the result of burning wood when temperatures in the flue are too low and/or the process of combustion is not complete…Stage three creosote is highly concentrated fuel and looks like a coating of tar running down the inside of your chimney.”

As you can probably tell, having “concentrated fuel” building up over your open wood fires is a recipe for disaster.

Why is creosote dangerous for your chimney?

Besides the unpleasant smell or the fact that creosote is corrosive to your chimney, the real danger with this pesky chemical buildup is that it’s extremely combustible. In other words, you’re almost quite literally sitting on a powder keg.

Having a flammable substance lining your chimney flue is one of the leading reasons why there are over 25,000 chimney fires in the U.S. each year causing damages upwards of $125 million.

But no one relays this message more clearly or more bluntly than the Chimney Safety Institute of America:

Dirty chimneys can cause chimney fires, which damage structures, destroy homes and injure or kill people.

So, at the end of the day, is creosote dangerous for your chimney? Yes, but the hard truth is that it’s even more dangerous for you and your family which is why it’s important to have your chimney inspected at least once per year.

If you’re located in Central Indianapolis, contact Brick + Ember Outfitters today to schedule your appointment and learn how safe your chimney is for this upcoming winter!