What Does Creosote Buildup Look Like?

If you enjoy watching flames pop and dance in your fireplace on chilly evenings, you need to learn what creosote looks like and how to eliminate buildup.

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Creosote is a natural by-product of burning fuel for heat and can't be avoided. The substance is highly flammable and may lead to dangerous and costly house fires, but regular chimney cleaning can manage unsafe levels.

What Does Creosote Look Like?

Creosote takes on many appearances. However, it's almost always black, gray or dark brown because it's made of material from your firewood that didn't burn completely.

Soot-filled creosote is powdery and looks like dust coating your fireplace and chimney. When it contains a mix of soot and tar, it may appear to be clusters of shiny black flakes that are sticky or oily.

The thickest and most dangerous buildup forms layers of tar covering the inside of your chimney. It's sometimes called glazed creosote because of the hardened, glistening surface.

What Does Creosote Smell Like?

You're most likely to notice the smoky smell of creosote if there's a downdraft in your fireplace. The sticky substance gives off an unpleasant acrid odor.

Depending on the severity of the buildup, it may smell foul or like tar, as if someone just paved an asphalt road. The smell often worsens in the spring and summer when the air is humid.

How Do You Know If You Have Creosote Buildup?

Because creosote can easily catch fire, it's important to complete an annual chimney inspection to safeguard your family and home.

There are several visual indications of creosote buildup besides a layer coating your chimney liner. You may notice:

• Chimney soot around the fireplace or wood stove

• Creosote deposits on the sides and glass doors

• Fewer ashes and more debris in the firebox

• Unusually dark smoke

The thicker creosote grows, the more you'll notice drafting problems. Fires won't burn as strongly and may go out unexpectedly. Over time, your home may not feel as warm.

What Are the Stages of Creosote Buildup?

Professional chimney sweeps refer to three stages of creosote buildup.

Stage One

This stage can easily be cleaned with a chimney brush. It's a thin layer of soot comprising dry or slightly sticky dust.

Stage Two

Left undisturbed, creosote thickens into a tarry substance that clings to your chimney in flakes or clusters. Cleaning it at this stage becomes difficult, as a simple brushing may not remove all the layers.

Stage Three

The final creosote stages end in a shiny glaze on your chimney liner. This hardened coat of tar requires specialized knowledge to clean. It may even be necessary to remove and replace the interior of your chimney.

Creosote, especially in high quantities, is highly flammable, which makes continued use of an unmaintained fireplace dangerous.

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How Do You Get Rid of Creosote in a Chimney?

The temperature of your chimney and moisture level of your firewood affect the amount and type of creosote left behind. For instance, wet and unseasoned wood burns poorly, releasing a high amount of unused carbon and tar into the air.

If airflow is poor in your chimney, smoke and soot will hang in the flue instead of exiting properly. Slowly flowing air gives creosote more time to adhere to the walls. A cold chimney can worsen this issue by causing the hot tar to condense and collect on the interior.

Proper operation of your fireplace helps creosote remain powdery in form and easy to clear away with a chimney brush or creosote cleaning log. Similarly, determined brushing and cleaning can usually scrub away stage two creosote, as long as large clusters are fully removed.

If you're unable to climb or uncomfortable climbing on your roof, you shouldn't put off calling professionals to maintain your chimney for you.

If you let maintenance slide, you'll need professional help to clear away any glazed creosote. When the substance reaches stage three, brushes will be ineffective. Professional chimney sweeps can try using chemicals and industrial-grade cleaners to break apart the layers, but the efforts may damage your liner.