As winter temperatures drop, many homeowners count on their fireplaces to keep their families warm. If it’s been some time since you last lit a fire, however, you may be surprised to notice an oily, flaky, or ashy substance falling from your chimney. This buildup, known as creosote, can leave you in need of emergency chimney repair or increase the risk of a chimney fire without prompt removal. Here's more about what this substance is and how to recognize it so that you can keep your family safe while enjoying the fireplace this season.

What Is Creosote?

Creosote is a concentration of tars and chemicals released by the burning of wood, coal, and other fuels. When wood and other natural materials are burned, their naturally occurring tar and chemical content turns into fumes that mingle with the smoke. 

When the smoke cools on stone, brick, and metal surfaces, the chemical content condenses into a solid substance. Over time, the creosote can become more concentrated, resulting in a range of consistencies and appearances.

What Are the Stages of Creosote Buildup?

Creosote forms and accumulates in three stages. In the first, it’s largely composed of soot and has a puffy consistency and appearance. First-stage creosote can be easily removed with a chimney brush, as the concentration of tars and other adhesive substances is too low to seal it to the chimney walls.

Second-stage creosote forms when a chimney is irregularly cleaned, fuel is burned improperly, or if there’s an issue in your chimney which disrupts the airflow necessary to remove byproducts. It usually appears as flaky, crunchy chunks or pellets during this phase.

When a chimney hasn’t been cleaned for excessive lengths of time, or if an airflow problem has trapped soot and smoke, vaporous creosote will cling to chimney walls and form a thick, black, oily coating. This is third-stage creosote, and it’s one of the most serious chimney fire hazards and causes of unexpected chimney repairs. This concentrated creosote is highly combustible and requires the attention of professionals to remove it safely.

If you notice creosote in your chimney at any stage, contact American Masonry & Chimney Corp in Rochester, NY, for assistance. Backed by over 50 years of industry experience, these fully licensed and insured professionals offer a full range of chimney repair and maintenance services to residents throughout Monroe and Erie counties. They'll safely remove the creosote buildup and make any necessary fixes so that your fireplace provides comfort to your family all season. Visit their website for more information on their services, or call (585) 865-4170 to request an estimate today.