by Marcus Pickett
There are 25,000 chimney fires in the U.S. each year, and nearly two-thirds can be attributed to a homeowner's failure to have the chimney cleaned. (The rest can be attributed to installation, construction, and design deficiencies.) You probably already know that you're supposed to have your chimney cleaned, but you may not know when, how, or why it's so important.
By far, the biggest danger lurking in your chimney is creosote. This material is a by-product of wood-burning fires caused by smoke that rapidly cools down in the chimney. Once enough creosote builds up, it can ignite violently and cause some of the hottest and most destructive residential fires possible. Witnesses have been known to describe the fire's sound as "a low-flying jet."
Often, a small chimney fire will set the stage for a larger inferno. Small creosote deposits can flare up and cause damage to the lining of your chimney. This, in turn, lets cool attic air into your chimney, accelerating the rate of creosote build-up, which can set the stage for disaster. In fact, some chimney fires don't even start in the chimney, but with rotted wood in attic spaces adjacent to a cracked chimney.
No regimen for wood-burning fireplaces can eliminate the build up of creosote, and these steps are in no way a substitute for cleaning. Yet, these preventative measures can slow creosote formation and reduce the likelihood that your chimney will catch fire between cleanings.
How often you should have your chimney cleaned really depends on how often you use your fireplace. If you only use your chimney once a week for a couple of hours at a time, you can probably go up to three years between cleaning service. For most homes, however, more regular use dictates annual cleaning. Heavy use may even require semiannual cleaning. The only sure way to know is to measure the creosote - a difficult prospect for some homeowners - to see if your flue is lined with creosote greater than 1/8-inch thick. If you haven't cleaned your chimney in a while, it's a safe bet that it's overdue.
If you're still not sure, the good news is a chimney inspection should cost only $50 to $100 and should answer virtually any question you have about your fireplace and chimney. Naturally, chimney cleaning is a bit more expensive with an average cost of $298, according to data collected from homeowners who actually hired a chimney sweep with ServiceMagic, the leading online resource connecting homeowners to home improvement contractors. The average cleaning takes about four hours, and if you're chimney sweep doesn't take at least one hour, you should be suspicious of the quality of the job.
-- Marcus Pickett is a senior home improvement writer with ServiceMagic.com. He has written more than 1200 articles on managing your home and home improvement trends.