Glossary · Fire & electrical safety
Creosote
Also called: creosote buildup · chimney fire
A flammable tar that builds up inside chimneys and flue pipes when wood smoke cools and condenses; too much of it can start a chimney fire.
What it means
Smouldering fires, wet wood and cold chimneys all increase creosote. CMHC's wood-heating guide says to check the flue often and clean it when deposits build up past about 4 mm (1/8 in.); older smoky stoves may need cleaning every few weeks, while efficient certified stoves may need it only once a year.
Why it matters in an audit
Regular sweeping keeps a wood stove safe, and because tightening a house can change how a stove drafts, its venting is part of a combustion safety check.
Typical numbers
Reference values with their sources. Your energy advisor’s report gives the figure for your own house.
| What | Value | Source |
|---|---|---|
| When to clean (CMHC wood-heating guide) | When deposits exceed about 4 mm (1/8 in.); as often as every few weeks for older smoky systems, about once a year for advanced stoves | publications.gc.ca ↗ |