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How to Tell if There Is Creosote Buildup in Your Chimney

According to the U.S. Consumer Product Safety Commission, more than 17,000 chimney-related fires occur in the U.S. each year, affecting homeowners from coast to coast.

To reduce the effects of chimney fires, the Chimney Safety Institute of America launched National Chimney Safety Week, an annual event to help improve education about the dangers of chimneys and to promote the safe use of indoor fireplaces. Each year, the organization shares tips and information for homeowners to help reduce the number of chimney fires and other carbon monoxide-related health emergencies in the U.S.

Fireplace in a home.

You should have your chimney professionally inspected, and if needed, cleaned each year, according to the National Fire Protection Association. Regular chimney maintenance, cleaning, and an annual inspection is the best way to prevent accidents, damage, and loss of life caused by chimney fires.

Chimney fires can go undetected by homeowners because they are often slow-burning fires and start inside the chimney. The resulting fire, however, can be just as damaging as other kinds of house fires, with explosions, high flames, and dense smoke affecting the entire home and putting residents at risk.


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What Is Creosote?

Creosote in a bucket.

Creosote is created when wood burns and smoke moves up the chimney and out of the home. The condensation from the rising heat sticks the residue to the inside of the chimney.

Creosote buildup increases when the air supply is restricted in the chimney, unseasoned wood is used to make a fire, and when the chimney temperature is cooler than normal. Too much creosote buildup can cause chimney fires and these low burning fires can go undetected until they spread.

How Can I Reduce The Buildup Of Creosote In My Chimney?

The three main conditions that increase creosote buildup can be minimized by homeowners. In addition, annual chimney inspection, maintenance, and cleaning can help reduce the buildup even more. First, ensure your chimney has adequate airflow before you start a fire. To do this, open the chimney’s damper wide so that the heated smoke can move up and out quickly. The longer the smoke is trapped inside a chimney, the more creosote can form inside it.

In addition, using unseasoned wood in an indoor fireplace also increases creosote buildup. This occurs because unseasoned wood takes more energy to start and burn at first, as water trapped inside the wood burns off. Overfilling your fireplace with wood can also increase creosote buildup.

How Do I Know When It Is Time To Clean The Chimney?

Responsible homeowners schedule an annual chimney inspection and if needed, professional cleaning. In addition, here are some signs to look for to let you know cleaning is needed:

  • Black oily spots on the inside of the fireplace
  • Fires are harder to start and keep going
  • More odor than usual is coming from the fireplace
  • Animal or pest activity in the chimney or fireplace

The black, oily residue seen inside a chimney is creosote buildup. If there is too much buildup inside the chimney, it can hinder the escape of smoke from the fire and impact how well the fire starts and burns. It can also cause a fire inside the chimney. If a homeowner notices a marked change in how well and long fires burn, a clogged chimney or a damper that’s not properly open or working may be causing creosote buildup.

An increase in odor from the fire, smelling more like a campfire than an indoor fireplace, is another sign of a dirty fireplace and chimney. This odor from creosote buildup can indicate an increased chance of chimney fires. Finally, if animals are found inside the chimney, they may be blocking airflow with their nests, which can also increase creosote buildup.

How Can I Remove Creosote From My Chimney?

If you notice any of the signs above, it’s time to schedule a professional chimney inspection and cleaning. In addition, a Creosote Sweeping Log can be purchased and burned in the chimney to help reduce buildup over time. The logs have chemicals that bond when they come into contact with the creosote in the chimney during burning. This can help reduce the creosote deposits inside a chimney and reduce the chance of fires in the future.

Along with maintaining a clean chimney free of creosote, it’s important for your chimney to be structurally sound. Oftentimes, chimneys are built on a different foundation separate from the rest of the home, and they can experience settlement differently by pulling away from the house.

To learn more about chimney and home maintenance or to schedule a professional inspection, contact a local foundation repair expert today.