Creosote removal. The thing that causes chimney fires.

Stage 3 creosote is the cause of most chimney fires. It is concentrated, flammable carbon — when it ignites, the flue can hit 2,000°F in seconds, crack the tiles, and ignite the framing around the chimney. The CSIA estimates 25,000+ chimney fires per year in the US, most caused by creosote buildup that was not removed.

No. Brushes will polish glazed creosote but cannot remove it. You need rotary chains driven by a drill, and for the worst cases, PCR chemical treatment that breaks the glaze down over 24–72 hours so it can be brushed out the next visit.

Two things: cool flue temperatures and unburned wood gas. Wood gas condenses on cool flue surfaces and deposits as creosote. Cool fires (smoldering, low-air, wet wood) make the most creosote. Hot fires with seasoned wood and a properly sized open damper make the least.

Not for Stage 3. CSL works on Stage 1 and light Stage 2 by changing the chemistry of the deposit so it brushes out easier. It does nothing on glazed Stage 3. Worse, some homeowners use it instead of an inspection — and miss the cracked liner that the buildup was hiding.

After removal we do a Level 2 camera scan to verify. Severe Stage 3 buildup sometimes hides cracked tiles or damaged mortar — and we will not sign off on the flue until we have looked. If repair is needed, we quote it before you light the next fire.