Questions about your chimney? Call our receptionist, Kari, at 320.414.0191. She picks up weekdays, 9 to 5.
Every wood fire leaves something behind in the flue, and that something is creosote, the tar and soot the smoke drops on the flue walls as it cools on the way up. A thin layer is normal. A thick one is fuel sitting inside your chimney, and it's what burns in a chimney fire.
What makes it build up faster
Wet or green wood makes a cooler, smokier fire. So does closing the damper down too far to make the fire last longer. Both cool the gases off before they get out the top, and the cooler the gases, the more they leave on the walls, until it hardens into a glaze that a brush won't touch.
When it needs to come out
That's what the inspection is for. If our technicians find more than an eighth of an inch of buildup, that flue will need to be swept. Heavy glaze takes a chemical treatment first. And if the liner is cracked, that's the bigger problem, because a cracked liner lets heat reach the chimney walls in a fire.
If any of this sounds like your chimney, call 320.414.0191. We'll come out, climb up, take pictures of what we find and show you before we quote anything.
Related: What our chimney inspection covers · Chimney flue relining