Creosote in Chimneys FAQ
Q: Is it necessary to clean my chimney if I burn seasoned wood?
A: More than necessary, it is essential to protect against costly and potentially fatal chimney fires. Creosote is a natural by-product of wood burning. The rate of creosote buildup is affected by residence time, smoke density and stack temperature. Animal nests and deteriorating mortar and cracked tiles are problems that need immediate attention. To insure your chimney is working safely and efficiently, have your chimney inspected and cleaned annually.
Q: How can a chimney catch fire?
A: The U.S. Consumer Product Safety Commission reports that each year about 30,000 residential fires originate in chimneys. Many of the fires are the result of the buildup of a highly combustible material called creosote. Once the chimney is coated with creosote, there is great potential for a serious chimney fire. At this stage, the flames from a burning newspaper could be sufficient to ignite the creosote. The substance burns rapidly and, as it spreads though the flue, creates a draft that intensifies the fire. As creosote burns, it peels and curls off the inside walls of a chimney, then drips into the flue and literally forms balls of fire that are propelled upward by the updraft. These fire balls shoot onto the roof and can quickly destroy a home. Fires can also occur due to high temperatures that melt mortar, crack tiles, and cause liners to collapse and damage the outer masonry material.
Q: What is creosote?
A: Creosote is a natural by-product of the wood burning process. It originates as condensed components in smoke, and dries to a flaky, solid or glazed form. It can be recognized in three distinct stages. First-stage creosote is flaky soot. Second stage creosote forms soft, gummy deposits. Third stage creosote is a hard, glazed substance that appears quite shiny and literally bakes onto the sides of a chimney. If there is a buildup of glazed creosote in your chimney, we recommend you immediately discontinue use of your stove or fireplace and contact a professional chimney sweep.
Q: What can I do about creosote in my chimney?
A: Our recommendation is shared by the National Fire Protection Association, fire chiefs, fire marshals, insurers and safety experts everywhere: KEEP YOUR CHIMNEY CLEAN! Homeowners should keep in mind that there are several conditions that promote formation of highly combustible creosote in chimneys, including burning unseasoned wood, restricted air supply and fires that do not burn at a high enough temperature. We recommend the following:
- Have your chimney cleaned and inspected on an annual basis by a certified chimney sweep.
- Between annual cleanings by a professional chimney sweep, use a properly sized chimney brush to clean the chimney.
- For on-going maintenance, apply a specially formulated creosote control product. These prevent creosote build-up and convert creosote over time into a dry, flaky substance that is easily removed.
- Use of a stove thermometer insures you are burning at the optimum temperature. If the fire is burning at a low temperature, it will promote soot and creosote buildup.
- To insure your firewood supply is properly seasoned and will have good heat content, have it split and stacked a year in advance.