Heading into heating season, creosote buildup is the most common reason a Lexington, KY chimney becomes a fire risk — but whether that risk is a sweep job or a repair job depends on what’s happening inside the flue.
Is Creosote Buildup Actually Dangerous?
Yes — creosote is flammable, ignites at temperatures a working fireplace easily reaches, and is a leading cause of residential chimney fires nationwide.
Creosote forms as smoke cools on its way up an unlined or under-used flue and condenses into a tar-like coating on the interior walls. NFPA guidance on heating safety points to annual chimney inspection and cleaning as the single most effective way to cut chimney fire risk. That inspection is a sweep’s job — we don’t clean flues — but what we find when a chimney has been neglected often isn’t just soot.
Can a Damaged Chimney Make a Creosote Fire Worse?
Yes — a cracked flue liner or open mortar joints let a creosote fire’s heat reach the wood framing around the chimney instead of staying contained in the flue.
A sound masonry chimney is built to contain a flue fire for long enough to be caught and extinguished. A liner that’s cracked from age or a prior chimney fire, or mortar joints open enough to let heat transfer through the wall, remove that margin — that’s the scenario where a contained flue fire becomes a structure fire. It’s also why we always recommend a liner and structural check alongside — not instead of — a sweep’s annual cleaning, especially on a chimney that hasn’t been inspected in several years. Most liner and structural repairs tied to fire-safety findings run in the same $300–$2,500 typical range as other chimney repair work here, depending on scope.
If your sweep flags a damaged liner or you’re seeing cracked mortar or a smoky smell along with heavy creosote, see our chimney repair warning signs page, or go straight to chimney repair & tuckpointing for how we handle the structural side.
Common Questions
Does Lexington Masonry Pros clean creosote out of chimneys?
No, sweeping and creosote removal is a certified chimney sweep’s job. We handle the masonry and structural side — liners, mortar, crowns — often after a sweep flags a problem.
How often should a chimney be inspected for creosote?
At least once a year for a regularly used fireplace, and sooner if you notice a strong smoky smell, reduced draft, or haven’t had one done in several years.
Can I check for a cracked flue liner myself?
Not reliably. A liner check needs a flashlight and mirror at minimum, and a camera inspection to catch hairline cracks — that’s part of what a proper chimney assessment covers.
Related: chimney repair warning signs · chimney sweep vs. chimney repair · chimney repair & tuckpointing. Back to Lexington Masonry Pros.
Lexington Masonry Pros · Serving Lexington & Fayette County, KY · Call or text (859) 310-1209
Last updated: September 3, 2026