Chimney relining in Geneva, IL
Stainless liners for cracked clay tile, unlined flues, and chimneys left the wrong size after a new furnace or a wood insert.
- Insured & Bonded
- 19 years in the trade
- Three brothers, one crew
- Open 7 days, 7am–8pm
A chimney needs relining when the flue is no longer a sealed, correctly sized passage — cracked or displaced clay tiles, open joints, an unlined flue in use, or a flue that is now the wrong size for the appliance attached to it. That last case is the most common and the least obvious: replacing a furnace with a high-efficiency unit leaves the original flue oversized, so exhaust cools and condenses instead of rising.
Smoke coming into the room, flames or roaring in the flue, or a carbon monoxide alarm sounding? Get everyone out and call the fire service first, then call us. We put these calls to the front of the queue.
What the liner actually does
The liner is the inner sleeve that carries smoke and combustion gases up and out. It does three jobs at once: it contains heat so the surrounding masonry and any framing near it never reaches ignition temperature; it protects the brickwork from acidic combustion byproducts that eat mortar from the inside; and it gives the system a smooth, correctly sized passage so it drafts properly.
An unlined chimney is doing all three of those with bare masonry, which was never designed for it. That was not negligence — lining simply was not standard practice when a lot of Fox Valley housing was built.
The oversized flue problem
This is the one we correct most, and it arrives disguised as good news. You replace an ageing furnace with a modern high-efficiency unit, the gas bills fall, everything works. A few years later there is damp on the chimney breast and crumbling mortar at the top of the stack.
An old furnace sent a large volume of very hot exhaust up the flue, which kept the gases moving fast and the flue walls above condensation temperature. A high-efficiency unit extracts far more heat into the house and sends much less up the chimney. That exhaust is cooler, wetter and lower in volume, and in a flue sized for the old appliance it loses heat quickly, slows, and condenses on the walls instead of rising.
The moisture that condenses out of gas combustion is acidic. It sits against mortar joints season after season, and the damage works from the inside outward — which is why it is usually years before anything shows. By the time you see white efflorescence on the brick or damp on the chimney breast, the process has been running a long time.
The same physics applies to a wood insert vented into a large open masonry flue without a properly sized liner. Sluggish draft, smoke rolling out when you open the door, and creosote accumulating far faster than it should.
What relining involves
A stainless liner, sized from the appliance’s output rating, the chimney height and the manufacturer specification — not from whatever happens to fit. It is fed down the existing flue, so the masonry stays where it is and nothing is rebuilt. On a straightforward single flue it is commonly a one-day job.
Insulation is usually worth it and sometimes required. Keeping flue gases hotter improves draft and sharply reduces creosote, and it maintains clearance safety where a chimney runs close to framing.
A properly sized stainless liner in a sound chimney is generally a once-in-the-life-of-the-house item.
When we will tell you not to
If the chimney has genuine structural failure — the stack leaning, widespread deep spalling, joints open through the wall — dropping a liner into it treats the wrong problem. We will say so rather than take the easier job.
If the appliance is a modern condensing furnace, the correct venting may not be the masonry chimney at all, and a liner would be money spent on the wrong thing.
And we are not going to tell you a two-hundred-year-old chimney is automatically dangerous and needs replacing. Plenty of old Fox Valley chimneys are sound and have decades left. The answer comes from the camera, not from the age on the deeds.
Furnace replaced but the chimney never touched?
Worth a camera inspection before another heating season.
Chimney relining questions
How do I know if my flue is the wrong size?
You generally cannot tell by looking. It is calculated from the appliance output rating, the chimney height and the manufacturer specification. That calculation is part of the inspection.
What are the warning signs?
White chalky efflorescence on the outside brick, damp on the chimney breast, crumbling mortar near the top of the stack, and rust on the appliance connector or damper.
Can individual cracked tiles be replaced instead?
Rarely practical. Clay tiles are buried inside the masonry, so reaching them means opening up the chimney, which usually costs more than lining it.
How long does relining take?
A straightforward single-flue reline is commonly one day. Offsets in the flue, masonry work needed first, or two flues in a stack all add time.
Is an insulated liner necessary?
Generally worth it and sometimes required. It keeps flue gases hotter, which improves draft and reduces creosote, and maintains clearance safety near framing.
Do I need to reline if I never use the fireplace?
Not for fire safety, since nothing is burning. It still needs a cap, and it is still worth inspecting because an open unused flue is a water route into the structure.
Will a liner fix my draft problem?
Often, yes. A correctly sized insulated liner in a previously oversized flue keeps gases hotter and moving, which usually improves draft noticeably.
How is a reline priced?
There is a published starting figure for scale, but a reline is quoted properly only after a camera inspection. See the pricing page.
Other things we do
All eight services come from the same three people.
Chimney sweeping · Chimney inspection · Chimney repair · Chimney caps & crowns · Gas fireplace service
Written by Rick Lee, owner of Zenith Chimney Service, Geneva IL. Published September 4, 2026.