The liner is the barrier that keeps heat and combustion gases inside your chimney and out of your home. When it cracks or corrodes, the chimney is not safe to use until it is relined. Here is how to know when relining is necessary.
What the liner does
The flue liner protects the surrounding masonry and the wood framing of your house from intense heat, and it keeps smoke and carbon monoxide from leaking into your living space. A compromised liner is a genuine fire and carbon-monoxide hazard.
Signs you may need relining
- Thin, curved pieces of clay tile showing up in the firebox
- A chimney fire — the heat can crack tile liners even if the outside looks fine
- Installing a new wood stove, insert, or higher-efficiency furnace
- White staining or moisture from an unlined or oversized flue
- An inspection that found cracks, gaps, or corrosion in the liner
Why a camera scan matters
You cannot judge a liner true condition from the firebox. A video camera scan during a Level 2 inspection shows exactly what is inside the flue — the only reliable way to confirm whether relining is needed.
What relining involves
Relining usually means installing a new, correctly sized stainless steel liner from the appliance to the top of the chimney, insulated as needed and capped. A quality stainless liner restores safe, code-compliant venting and can last for decades.
Think your liner may be damaged?
Careful work, up-front pricing, seven days a week in La Grange and the western suburbs.
Call (708) 432-5330Frequently asked questions
How do I know if my liner is cracked?
The reliable way is a flue camera scan during a Level 2 inspection. Tile shards in the firebox or a recent chimney fire are warning signs, but only a scan confirms it.
Do I have to reline after a chimney fire?
Often yes. Chimney fires reach temperatures that crack clay tile liners even when the outside looks undamaged, so a Level 2 inspection afterward is essential.
Why does a new stove need a new liner?
A modern stove or insert usually requires a specific, smaller flue size to draft and burn efficiently and safely. An oversized old liner causes poor draft and more creosote.
How long does a stainless steel liner last?
A quality stainless liner, properly installed, can last for decades and usually carries a strong warranty, resisting the cracking and corrosion that shorten older liners.
Written by Adam Evans, owner of Chimney Sweep Brothers and a chimney technician with 12 years of experience serving La Grange, IL and the western suburbs.