The liner is the safety barrier between combustion gases and your framing. Here is when it has to be replaced.
The liner keeps heat and combustion gases inside the flue and away from the wood framing packed against your chimney. When it fails, the chimney is not safe to use — regardless of how good the brick looks.
When replacement is required
- Cracked, spalling or shaling clay flue tiles
- Gaps in mortar joints between tiles
- Any chimney that has had a chimney fire
- A conversion to a new appliance or fuel type — a wood flue is almost always oversized for a gas insert
- Older Cincinnati homes with no liner at all, which was legal when they were built
- An inspection report flagging liner deterioration
Liner options
| Type | Notes |
|---|---|
| Flexible stainless | Most common; fits offsets and older chimneys |
| Rigid stainless | Straight runs; slightly better flow |
| Insulated stainless | Required for many wood appliances; improves draft |
| Cast-in-place | Restores structural integrity in deteriorated masonry |
Sizing matters more than material
An oversized flue lets gases cool before they exit, which causes condensation, creosote and poor draft. An undersized flue cannot vent the appliance. The liner must be sized to the specific appliance — this is the single most common error we find on other companies' installs.
A correctly installed, insulated stainless liner is a lifetime component in most homes.
Frequently Asked Questions
How much does chimney relining cost?
In the Cincinnati area, stainless relining typically runs $2,000 to $4,500 depending on flue length, insulation and appliance type.
Can I use my fireplace with a cracked liner?
No. Cracked tiles let heat and carbon monoxide reach framing and living space. The fireplace should not be used until it is relined.
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