How often should a chimney be swept in Illinois?

The short answer is once a year. The EPA's Burn Wise program and NFPA 211 both put an annual inspection on the calendar for any chimney that vents a fireplace, wood stove or gas appliance, whether or not you burned much last winter.

Why a year, and not "when it looks dirty"

Creosote is the obvious reason, but it is rarely the one that costs people money. In our part of Illinois the freeze-thaw cycle does more damage than smoke does. Water gets into a crown crack or an unlined joint in November, freezes in January, and opens the crack a little wider every night. By spring a hairline is a gap. A yearly look catches that while it is still a tube of sealant instead of a rebuild.

What the annual visit actually finds

• Creosote build-up in the flue, and how fast it is forming
• A cracked or missing crown, a rusted or missing cap
• A damper that no longer seals — a year-round heat leak
• An unparged or corbelled smoke chamber, the most common cause of a smoky fireplace
• Nests, leaves and animal debris blocking the draft
• Gas appliance connections, pilot and safety shut-off

If you burn a lot

A household burning several cords a season, or burning unseasoned wood, may need a mid-season sweep as well. The rule of thumb sweeps use is one-eighth of an inch of creosote — at that point it comes out, regardless of the date.

Best time to book

August through October. Once the first cold snap arrives everyone calls at once, and any repair we find needs dry weather and mortar cure time. Booking early means the fireplace is ready the first night you want it.