What Causes Chimney Fires and How to Prevent Them

Every winter in Kansas City, fire departments respond to dozens of chimney fires that could have been prevented. Most homeowners don’t even realize their chimney is burning until they hear a sound like a freight train roaring through their living room.

The Real Culprit: Creosote Buildup

Here’s what most people don’t know about their chimneys. Every time you burn wood, smoke rises up the flue and leaves behind a residue called creosote. It’s a tar-like substance that sticks to your chimney walls, and it’s extremely flammable.

Creosote comes in three stages. Stage one is flaky and relatively easy to brush away during a cleaning. Stage two gets sticky and harder to remove. Stage three? That’s the dangerous one. It becomes a hard, glazed coating that looks almost like melted tar has been painted on your chimney liner. You can’t just brush this stuff off, and it can ignite at temperatures as low as 451 degrees Fahrenheit.

The speed at which creosote builds up depends on how you burn your fires. Slow-burning, smoldering fires produce way more creosote than hot, fast-burning fires. When wood doesn’t burn completely, all those unburned particles head straight up your chimney and stick to the walls.

Kansas City Weather Makes It Worse

Our weather patterns here don’t do us any favors. Those temperature swings we get—where it’s 55 degrees one day and 20 the next—create condensation inside your chimney. That moisture mixes with the creosote and makes it even stickier and more combustible.

During our cold snaps in January and February, people tend to load up their fireplaces and let them smolder all evening. It feels cozy, but you’re basically creating a creosote factory. The cooler the fire burns, the more residue gets left behind.

Other Common Causes

Creosote isn’t the only problem, though it’s definitely the biggest one. Burning the wrong materials accelerates everything. Cardboard, wrapping paper, pine needles, and treated wood all produce more creosote than seasoned hardwood. I’ve seen chimneys that looked like they hadn’t been cleaned in decades, and it turned out the homeowner had just been burning whatever was convenient.

Green or wet wood is another major offender. Wood needs to be seasoned for at least six months, preferably a year. When you burn wet wood, it produces more smoke and burns at a lower temperature. Both of those factors mean more creosote.

Restricted airflow causes problems too. If your damper is partially closed or you’ve got debris blocking the flue, smoke can’t escape properly. It lingers in the chimney, cooling down and depositing even more residue on the walls.

What Actually Happens During a Chimney Fire

Look, chimney fires are terrifying. Some are explosive and dramatic—you’ll hear loud cracking sounds, see flames shooting out the top of your chimney, and smell intense smoke throughout your house. Your neighbors might see sparks and dense smoke pouring out of your chimney like a volcano.

But here’s the thing that scares me more: slow-burning chimney fires. These can burn at high temperatures without anyone noticing. You might not hear anything or see visible flames. The fire just quietly burns through creosote deposits and can crack your flue liner or even damage the structure of your chimney. We’ve inspected chimneys after the fact where homeowners had no idea they’d even had a fire.

Either way, a chimney fire can reach temperatures above 2000 degrees. That’s hot enough to crack masonry, melt metal components, and ignite nearby combustible materials in your walls or roof.

Prevention Isn’t Complicated

The best prevention is also the simplest: get your chimney cleaned and inspected annually. The National Fire Protection Association recommends it, and honestly, it’s just common sense. A professional sweep can remove creosote before it becomes dangerous and spot other issues like cracks in your liner or deteriorating mortar joints.

For most Kansas City homeowners who use their fireplace regularly through winter, scheduling a cleaning in late summer or early fall makes the most sense. You’re ready to go before that first cold snap hits in November.

Burn the right wood. Seasoned hardwoods like oak, maple, and ash burn hotter and cleaner than softwoods. Store your wood off the ground in a covered area where air can circulate around it. If you’re buying wood, make sure it’s been seasoned properly. You can test it yourself—seasoned wood sounds hollow when you bang two pieces together, and the ends will have cracks radiating from the center.

Keep your fires hot. I know it’s tempting to dampen down your fire and let it smolder, but resist that urge. A hot fire burns more completely and produces less creosote. Get a good blaze going and maintain it rather than creating a smoky, cool fire.

Install a Chimney Cap

If you don’t have a chimney cap, get one installed. They’re not expensive, and they prevent animals from nesting in your chimney during the off-season. Bird nests and other debris block airflow and create fire hazards. Plus, caps keep rain out, which reduces that condensation problem I mentioned earlier.

Watch for Warning Signs

Your chimney will often tell you when something’s wrong. If you notice a strong, smoky smell even when you’re not using your fireplace, that could be creosote buildup. A damper that’s hard to open or close might indicate warping from excessive heat. Any crumbling or damaged mortar on the exterior of your chimney needs immediate attention.

You should also pay attention to how your fires burn. If smoke regularly backs up into your house or you’re having trouble getting fires to draw properly, something’s blocking your flue. Don’t just live with it—get it checked out.

What to Do If You Have a Chimney Fire

First, call 911 immediately. Don’t try to be a hero. Get everyone out of the house.

If you can do it safely, close the damper and glass doors to cut off the fire’s oxygen supply. Don’t use water on a chimney fire—it can cause a dangerous steam explosion and crack your flue liner. Just get out and let the fire department handle it.

After any chimney fire, even a small one, you need a professional inspection before you use that fireplace again. The heat may have compromised your chimney’s structural integrity in ways that aren’t visible from the outside.

It’s Really About Consistency

Preventing chimney fires isn’t about doing one big thing right. It’s about consistent maintenance and good burning practices throughout the season. Clean your chimney annually, burn seasoned hardwood, keep your fires hot, and pay attention to how your system performs.

We’ve been cleaning and inspecting chimneys throughout the Kansas City metro area for years, and the homeowners who never have problems are the ones who stay on top of maintenance. It’s that simple. If you can’t remember the last time someone looked at your chimney, or if you’ve been using your fireplace regularly and haven’t had it cleaned this year, now’s the time to schedule an inspection. Don’t wait until you hear that freight train sound.