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:
1. Have your chimney cleaned and inspected on an annual basis by a certified chimney sweep.
2. Between annual cleaning by a professional chimney sweep, use a properly sized chimney brush to clean the chimney.
3. For on-going maintenance, apply one of our creosote control products. They are specially formulated to prevent creosote build-up and convert creosote over time into a dry, flakey substance that is easily removed.
4. 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.
5. To insure your firewood supply is properly seasoned and will have good heat content, have it split and stacked a year in advance.
Q. Is creosote the only problem I have to contend with in my chimney?
A. While creosote is a major concern, it is not the only concern. Leaves, birdnests or debris from your heating system can block your chimney. A crack or break in the flue tile can interfere with the chimney’s ability to vent properly. If you have experienced a chimney fire and the flue temperature exceeded 2000°F, the mortar might melt, tiles could be cracked, or the liner might have collapsed. An inspection by a certified chimney sweep will uncover any of these issues.
Q. How can I find a certified chimney sweep in my area?
A. Please visit the National Chimney Sweep Guild at www.ncsg.org. They are the organization that trains and certifies professional sweeps.
Q. What is the difference between soot and creosote?
A. Soot is primarily composed of unburned carbon particles, but may also contain ash. It has a soft texture and is black or brown in color. The flammability of soot will depend on the concentration of soot and ash. Soot is combustible, since it is made of carbon. Ash is noncombustible.
Creosote is a deposit that is a by-product of incomplete combustion. It is either curly, flaky deposits, gummy or bubbly deposits. It is flammable. The next stage is glaze, which is described as a shiny, tarry substance. Glaze can form puddles or drip down and make formations that resemble black icicles. Glaze is the densest type of chimney deposit and, therefore, represents the greatest amount of fuel to burn in the event of a chimney fire. Glaze is also the most difficult type of deposit to remove from the chimney.
Q. I have heard of a product called Chimfex to help put out chimney fires. Where can I purchase it?
A. Chimfex has not been available for several years, but it will be back on the market in July, 2009. Any of our customers will be able to sell it to you.
Q. What should I use to seal the joints in my metal stove pipe to keep the smoke from coming out?
A. We recommend Rutland’s Seal It Right. It can be used in temperatures up to 800°F. It flows to create a gasket, but will also allow you to take the pipes apart for inspection and cleaning.
Q. What is the difference between an airtight stove and a free-burning or non-airtight stove?
A. Generally, an air-tight stove is one that has carefully fitted seams, has a door that seals tightly, and an air inlet that controls the burn rate. A free-burning stove is one with a loose fitting door and without good air regulation. It may also be a stove that can be operated with the door open or closed.