Worried about creosote? Here’s what to look for

Worried about creosote? Here’s what to look for is one of our three-part series about chimney maintenance, along with:
Chimney 101: get to know your smokestack
The essential guide to cottage chimney maintenance

What is creosote? It’s the tarry remnant of incomplete combustion that fuels chimney fires, and soot, the flammable residue of unburned carbon. The fire code mandates an annual chimney checkup, though the fire code doesn’t specify who must do the inspection. Some insurers require occasional WETT inspections, but in practice many “annual inspections” are probably conducted by cottagers when they clean their chimneys. Nevertheless, it’s a good idea to have a WETT-trained inspector or chimney sweep in to check the system. 

Between inspections, here are some of the things you can look for:

The woodstove “dashboard”: Everyday signs of clean burning 

1. Glass on woodstove or fireplace insert is clear, or with only a slight haze after an overnight burn.

2. Firebox deposits are tan or light grey.

3. No visible smoke from the chimney when fire is hot.

4. Chimney cap that’s relatively clean and shiny. 

The chimney checkup: Looking for creosote deposits

Bad sign: When stage three creosote ignites, “it puffs up to 1,400 times its original volume. It looks like an Aero chocolate bar,” says Zigi Gadomski, president of WETBC. Traces of puffy, black creosote on the chimney cap, roof, or ground could mean you’ve already had a fire. 

Other problems: Nests, leafy debris, forgotten tools. “We got a call once: ‘Our chimney’s not working!’” says Yvette Aube, of AIM Chimney Sweep and Stove Shop. “Turned out there was a plastic chimney brush stuck in it.”

Read more:

Chimney 101: get to know your smokestack

This article was originally published as part of”Up in Smoke” in the Fall 2021 issue of Cottage Life. Read the rest at The essential guide to cottage chimney maintenance.

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