How often do you need to have your chimney cleaned? It depends on the moisture content of the wood you burn. If you burn mostly green (wet) logs, have your chimney cleaned or inspected every 50 burns. If you see moisture bubbling out the ends of the logs when they're burning, the wood is wet. This green wood doesn't burn cleanly and sends a lot of unburned particles (smoke) up the chimney, where they build up as creosote and soot. Dry hardwoods, such as oak and birch, burn hotter and cleaner. With them, have your chimney cleaned or inspected every 70 burns. A chimney cleaning costs $225 to $400.
Creosote and soot buildup in the chimney flue is dangerous because it can ignite and cause an uncontrollable chimney fire. A quick way to tell if your chimney needs cleaning is to run the point of your fireplace poker along the inside of your chimney liner (see photo). If you find a 1/8-in. or more layer of buildup (the thickness of a nickel), call a chimney sweep. The chimney sweep we talked with said he sees 40 to 50 chimney fires a year, and more than half of the chimneys he services require extra cleaning because the homeowners wait too long before calling. In extreme cases, the hardened layer of buildup requires cleaning with special tools or chemicals.
If it's been a few years since your last chimney cleaning, now's a good time to schedule one. The cleaning includes an inspection for soot buildup, obstructions, cracks in the chimney liner and signs of water damage. Older chimneys often have gaps between clay liner sections where the mortar has fallen out.
