Chimney sweeps provide an essential service for all fireplace owners, particularly those with wood burning heaters. While some chimney maintenance can be done by the homeowner it is vital to have a professional chimney sweep inspect and clean the chimney at least once a year. The necessary frequency of these checks will depend on how often the fireplace is used and what sort of fuel is burned.
The first thing a good chimney sweep will do is lay down some tarp in order to protect your house from soot and dust. They will then proceed to check the structural steadiness and reliability of the chimney. Some sweeps will repair structural damage while others will recommend someone who can but most will not clean the chimney until the damage has been repaired. Most consultations will include an evaluation and cleaning service unless cleaning is not necessary. Some chimney sweeps prefer to clean from the top and then from the bottom while others only clean from the bottom, using long brush extensions to reach the top. Either of these methods is acceptable. Cleaning from the top only, however, is not as soot and creosote will fall into the fireplace and continue to be a fire hazard.
Thoroughly checking and cleaning a chimney normally takes about 30 to 60 minutes, anything less than this is not enough to sufficiently clean a chimney. Once the chimney has been cleaned a high-powered vacuum cleaner is used to clean away the soot and creosote that has fallen into firebox.
Regular professional cleaning is particularly important in the prevention of chimney fires. These are caused by the build-up of a highly flammable substance called creosote on the chimney lining. Creosote is the result of condensed smoke that forms due to incomplete combustion. Chimney fires can vary in size and severity. In some cases the fire will be confined to the chimney but sparks and heat could ignite other flammable substances nearby, such as the roof. Cracked or damaged chimney liners could allow the fire to spread to other areas of the house.
According to statistics published by the U.S. Consumer Product Safety Commission for 1988, 65,200 residential fires in the 50 states were related to chimneys, fireplaces, woodstoves and other solid fuel appliances. These are fires that may possibly have been prevented with regular chimney inspection, cleaning and repair.
The first step to having a healthy fireplace is by burning the right fuel. Never burn garbage, plastics, foil, coated paper, or painted or chemically treated scrap wood. In addition to causing an unfavorable build up on the interior of the firebox and chimney, these also produce noxious fumes which pollute the air (in & out of the home). Burn only seasoned split wood. Seasoning allows moisture in wood to evaporate. Forty-four per cent more heat can be generated from a seasoned log. A clean burning fire is a hotter fire with good drafting conditions that produce cleaner combustion and less smoke from the chimney.
The next step is to have your chimney inspected by a professional chimney sweep annually and, if necessary, cleaned of soot and creosote which is a chemical substance that forms when wood burns. It is the heavy creosote build up that becomes highly flammable often resulting in explosive chimney fires. According to the National Chimney Sweep Guild (NCSG), a national trade association for chimney sweeps, a visual inspection is all that is required for most chimneys. Whereas fees vary according to height and configuration of the fireplace, most visual inspections range from $35. to $60.
In the case where a visual inspection is not adequate, many chimney sweeps are now equipped to do more elaborate inspections with a video camera and monitor referred to as a “chimscan”. The chimscan is more costly than the visual inspection ($100 to $200), but will reveal significantly better information about the condition of a chimney. This is especially important when the integrity of the flue is in question due to age or damage from an earthquake or chimney fire.
Finally, as part of his inspection and cleaning, the chimney sweep will also make comments relative to the condition and operation of the damper and spark arrester. Frequently, these will either not exist or are in such a state where they need replacement.
The damper is a steel or cast-iron door that opens or closes the throat of the firebox into the flue. It regulates draft and prevents the loss of heat up the chimney. The spark arrester is a cage-like device which is secured to the top of the chimney. It prevents sparks and ash from escaping and causing a fire on the roof or other potentially flammable substance. It will also keep squirrels, birds and raccoons from nesting in the chimney. Nesting materials can cause a serious safety hazard. Their droppings pose health risks because diseases may be transmitted through their fecal materials. A spark arrester will prevent this.