By Grant Hiatt ¦ Technical Writer & Editor

Although the image of soot-blackened Victorian chimney sweeps is outdated, professional chimney cleaning—and the attendant benefits—is still as important as ever. Clogged or neglected chimneys are not only less efficient and smellier, but they can also pose safety risks.

Two Potential Dangers: Chimney Fires and Carbon Monoxide

The common cause of many chimney safety issues is known to professional chimney sweeps as creosote, which is a tarry buildup of soot and ash. Creosote can constrict flues, conceal dangerous leaks and structural damage in chimneys, and, under hot enough temperatures, ignite. When creosote ignites, the result may be a chimney fire—one that can burn hot enough to weaken the chimney’s masonry or start a house fire.

Homeowners should be able to recognize the various signs of chimney fires. Although chimney fires often burn loudly and explosively, sometimes relatively quiet tinkling or crackling sounds within a chimney may be the only signs of smoldering creosote. If you do encounter a chimney fire, evacuate your family immediately. Then, if it’s safe to approach the hearth, extinguish the flames in the fireplace with sand or a fire extinguisher, close the fireplace doors to remove the fire’s oxygen supply, and call the fire department for additional assistance.

Poorly maintained chimneys may also constitute a dangerous source of carbon monoxide. Leakages and blockages caused by creosote, soot, and other debris can vent toxic gasses back into the house. According to the EPA, over 200 people in the US die every year from carbon monoxide poisoning due to venting problems with fireplaces or heating appliances.

Scheduling Chimney Inspections and Sweepings

By scheduling regular chimney inspections and sweepings, homeowners can avoid chimney fires, prevent carbon monoxide leakage, and reap other benefits as well. In addition to being safer, a properly swept chimney is also more efficient, less smoky, and better smelling. Removing soot and creosote from the chimney increases the diameter of the flue and allows smoke to escape more easily. A clean flue also creates a better draft and a fire that burns more efficiently.

Homeowners should have their chimneys inspected at least once annually and professionally cleaned whenever there is an excess of creosote in the flue. According to the Chimney Safety Institute of America (CSIA), homeowners should schedule a chimney sweeping when their flues have between one-eighth and one-fourth inches of creosote buildup.

With the proper protective equipment, such as safety goggles and a dust mask, you can inspect for creosote yourself. First, open the damper and shine a flashlight upward into the smoke chamber. Note that creosote goes through several different stages as it forms, so look for buildup that may be gray and sooty, black and tarry, or shiny and hard. Use a fire poker to probe any layers of buildup. If the creosote is between one-eighth and one-fourth inches thick, schedule a sweeping. If the creosote is thicker than one-fourth of an inch, do not use the fireplace until the chimney has been swept.

Although gas is a clean-burning fuel that does not contribute to the buildup of creosote deposits, the CSIA points out that gas fireplaces should also be checked annually for structural integrity and natural debris like bird nests.

Chimney sweeps are busiest during winter, so try to schedule an inspection during the off-season. If an inspection reveals that you need a professional cleaning, you may save money and avoid a long wait by scheduling your chimney maintenance in the spring. Make sure the chimney sweep you hire is knowledgeable about building codes and trained to recognize deterioration or venting problems. For even more tips on how to maintain your chimney so that it’s operating at its best, check out part two of our blog this Thursday.