An unlined chimney has no inner sleeve between combustion gases and the surrounding masonry, because flue lining was not standard practice when much of Elgin was built. If the flue is not in use it is a weather and animal problem. If it is in use, gases contact mortar joints directly and erode them over decades — which becomes a clearance problem invisible from inside the house.
What the liner does
The liner is the inner sleeve that actually carries smoke and combustion gases up and out. It does three jobs simultaneously. It contains heat so the surrounding masonry, and any framing timber 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 jobs with bare masonry, which was never designed for it.
Why it was built that way
Not negligence. Lining simply was not standard when much of Elgin’s older housing went up. Many of those chimneys served coal stoves originally, and were then adapted for oil and later gas without anyone revisiting the flue. Each of those fuel changes altered what the chimney needed to do.
What it means practically
An unlined flue that is genuinely not in use is a weather and animal problem, not a fire risk — it still needs a cap, and it can still be a water route into the structure.
An unlined flue that is in use is different. Combustion gases are in direct contact with mortar joints, and over decades those joints erode. Where the erosion opens a path toward framing, you have a real clearance problem that is invisible from inside the house. This is exactly what a camera inspection is for.
The realistic fix
A stainless liner, fed down the existing flue and insulated, sized to the appliance. The masonry stays where it is; nothing is rebuilt. It is a one-day job on a straightforward chimney, and a properly sized stainless liner in a sound chimney is generally a once-in-the-life-of-the-house item.
The exception is a chimney with genuine structural failure. Dropping a liner into a stack that is coming apart treats the wrong problem, and we will say so rather than take the easier job.
What we will not tell you
That a two-hundred-year-old chimney is automatically dangerous and needs replacing. Plenty of old Elgin chimneys are in sound condition and have decades left. The answer comes from the camera, not from the age on the deeds.
How a liner is actually fitted
People often assume relining means rebuilding, and it usually does not. A stainless liner is a flexible or rigid pipe fed down the existing flue from the top, sized to the appliance, then connected at the appliance end and sealed at the top with a cap and a plate. In most cases the only access needed is the roof and the firebox. Where the flue has offsets or a tight bend the job takes longer and occasionally needs a small opening made, but the masonry stack itself stays exactly where it is. Insulating the liner — either with a wrap or poured insulation around it — is what turns it from a barrier into a system that also drafts well, because keeping the gases hot is what keeps them moving.
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Old house, unknown chimney?
A camera inspection tells you exactly what you own. No guesswork.
Related questions
How do I know if my chimney is unlined?
A camera inspection is the only reliable way. The upper flue is what matters and you cannot see it from below.
Is an unlined chimney illegal?
Existing chimneys are generally not required to be retrofitted simply because standards changed. The issue is safety in use.
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 is worth inspecting once.
Can individual cracked tiles be replaced instead?
Rarely practical. Clay tiles are buried inside the masonry, so reaching them usually costs more than lining it.
How long does relining take?
A straightforward single-flue reline is commonly one day.
Will a liner fix my draft problem too?
Often, yes. A correctly sized insulated liner keeps gases hotter and moving.
Written by Rick Lee, owner of Zenith Chimney Service, Geneva IL. Published September 19, 2026 · Last updated September 4, 2026.