Fireplace Chimneys and the Dangers of Creosote

I grew up in Minnesota. I think everyone had a fireplace. Actually, most folks had 2 or 3 fireplaces. What else could you do in the winter except sit next to the fireplace, right? (Well, I’m kidding – I kept busy skiing, skating, snowmobiling, snowshoeing, sledding, making snowmen, instigating snowball fights, and my favorite of all…hitching our dog to a plastic sled I sat in and throwing tennis balls for her to fetch! Ahhh, the life of a kid growing up in Minnesota!)

But it wasn’t until adulthood that I learned some important ins and outs about fireplaces. Obviously, there are the basics; don’t leave the fireplace unattended, watch the kiddos, don’t use a vacuum to clean up ashes, don’t touch the glass door when in use, only use dry wood (duh!), use fireplace utensils to move logs around, and be sure to open the damper prior to starting the fire, (again, duh!).

But what I did not know was how buildup inside the chimney could be a huge fire hazard. That’s right, the build up is called creosote. So, in case this is new to you, here is Creosote 101.

  1. Creosote is a byproduct of wood combustion that consists mainly of tar. Traces are found in the smoke that rises from open flames; and when the smoke travels upward and mixes with cold air and water near the top of a chimney, it solidifies and sticks to the chimney liner. Here’s a factoid – creosote is actually what gives “smoked” meat its distinctive flavor, scent, and stability.


  1. There is really no way to stop creosote from forming. Small amounts of it will form every time you use the chimney. Small amounts are okay. But after numerous fires, it builds up and in the 3rd stage it becomes like an oily tar like substance – and very flammable.
  1. To avoid a toxic substance (or situation), it’s a good general rule is to clean the chimney after about 50 uses. Some experts suggest you do it each year before the winter season begins.
  1. I have heard a few people shortcut the process and use a “Creosote Sweeping Log” that you can buy at home improvement stores or on Amazon for about $20. Manufacturers claim it reduces the weight, thickness and flammability of creosote. Me…I am not going to take a chance. Hire a professional to clean it. See the next point.
  1. Hire a professional to inspect and clean your chimney, just like the chimney sweeps you saw as a kid in Mary Poppins. Really, they use huge brushes and other tools to scrape the lining. Just not sure they can dance like Dick Van Dyke, but you can always ask them! Best to hire a pro that has the “Certified Master Chimney Technician” certification offered by the Chimney Safety Institute of America. It’s actually a rather impressive certification that requires 8 years of practice to acquire the certification.

    Tools of the Trade

So, there you have it. Stay warm and STAY SAFE! Call your local Chimney Sweep before it gets any colder this winter.

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