Creosote: What It Is, Why It's Dangerous, and How to Prevent It

By Chimney Cleaners Editorial · January 8, 2026 · 5 min read

Creosote is the tar-like fuel that causes 25,000+ chimney fires every year in the US. Here's how it forms and how to keep it out of your flue.

Creosote is what happens when wood smoke condenses on a cool flue wall. It starts as a light, sooty powder (Stage 1), thickens into flakes (Stage 2), and eventually hardens into a shiny black glaze (Stage 3) that ignites at just 451°F.

The three stages

Stage 1: Loose, powdery soot, removed with a standard sweep.
Stage 2: Puffy, flake-like deposits, requires rotary tools.
Stage 3: Glazed, tar-like coating, requires chemical treatment (PCR) plus rotary extraction.

How to prevent it

Burn only seasoned wood (moisture below 20%)
Never burn softwoods or construction scrap in a fireplace
Let the fire breathe, starving it produces more smoke
Insulate exterior flues to keep them warm
Sweep annually

Chimney Sweeping in the towns this guide covers

Each local page lists pricing, code notes, and scheduling for that municipality:

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Nearby New Jersey towns we cover

Not in one of the towns above? These are the regions where this issue comes up most, with a dedicated local page for each municipality.

Older urban housing stock

Pre-1940 row houses and multi-family buildings commonly have unlined or shared flues.

North Jersey freeze-thaw belt

Repeated freeze-thaw cycles open mortar joints and spall brick faster than the rest of the state.

Central & suburban New Jersey

Post-war and 1980s subdivisions where prefab fireboxes and factory chases dominate.

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