The liner is the part of your chimney that actually keeps the house safe. Ace Chimney Service installs stainless steel liners for fireplaces, wood stoves, inserts, furnaces, and water heaters throughout Crystal Lake and McHenry County.
What the liner does
A chimney is not simply a hole through the roof. Inside the masonry there is a liner, and it does three jobs at once: it contains the heat so the surrounding brick and the wood framing beyond it stay at safe temperatures, it carries combustion gases including carbon monoxide out of the building, and it protects the masonry from the acidic byproducts of combustion.
When the liner fails, all three protections go at once. That is why a cracked liner takes a fireplace out of service until it is fixed — it is not a cosmetic fault.
How liners fail
Most older Crystal Lake homes have clay tile liners, and clay has a predictable set of weaknesses. A chimney fire heats the tiles far faster than they can expand, and they crack. Water entering through a failed crown or missing cap gets into the joints between tiles and freeze-thaw opens them up. Mortar between tiles washes out over decades, leaving gaps.
There is also a mismatch problem. Many chimneys were built for an old, hot-burning appliance. Replace that with a modern high-efficiency furnace and the flue gases come out cooler and much wetter. That condensate is acidic, and it eats clay and mortar from the inside.
Stainless steel relining
A stainless liner is a continuous flexible or rigid pipe run the full height of the chimney and sized to the appliance it serves. Because it is one unbroken piece, there are no joints for gases to escape through — which is exactly the failure mode of an old tile system.
Sizing is the part that matters most and is most often got wrong. A flue that is too large lets exhaust cool on the way up, which weakens draft and accelerates creosote buildup. Too small and the appliance cannot vent. We size to the appliance and the chimney’s height, not to whatever happens to be on the van.
We insulate the liner in most installations, particularly on chimneys running up an exterior wall. Insulation holds flue temperature up, which improves draft and cuts creosote formation substantially — the same problem described on our chimney sweeping page, addressed at the source.
Finding out whether you need one
You cannot judge a liner by looking up the fireplace. It requires a camera scan of the full flue, which is part of a Level 2 inspection. If the liner is sound, we will tell you so. If it is not, you get the footage and a clear explanation rather than an assertion.
Water is behind a great deal of liner damage, and water almost always enters at the top. Where that is the case, crown and cap work is part of the fix — otherwise the new liner is installed into a chimney that is still letting water in.
Booking
We cover Crystal Lake and the surrounding McHenry County towns, 7am to 7pm, seven days a week. Call (815) 320-0883 or request an appointment. Relining pricing is on our pricing page.
Frequently Asked Questions
How do I know if my liner has failed?
You usually cannot see it from below — it takes a camera scan. Warning signs include pieces of clay tile in the firebox, a persistent smoke smell, white staining on the exterior masonry, and draft problems that sweeping does not fix.
How long does a stainless steel liner last?
A quality stainless liner installed correctly and swept regularly is generally expected to last for decades, and reputable liners carry long manufacturer warranties. Burning unseasoned wood and skipping annual sweeps shortens that considerably.
Why do clay tile liners crack?
Clay expands and contracts slowly. A sudden intense heat load — a chimney fire being the obvious one — expands the tile faster than it can cope with, and it cracks. Water and freeze-thaw finish the job over time.
Can I keep using the fireplace with a cracked liner?
No. A cracked liner lets heat and combustion gases reach the wood framing around the chimney, and it lets carbon monoxide into the house. It needs to be out of use until it is relined.
Does a new furnace need a new liner?
Frequently, yes. Modern high-efficiency appliances exhaust cooler, wetter flue gases than the chimney was built for. That condensate attacks clay and mortar, so an appropriately sized liner is often required.
How long does relining take?
Most straightforward relines are completed in a day. Chimneys with offsets, unusual dimensions, or a flue that has to be opened up can take longer.
Is an insulated liner worth it?
In most cases yes, especially on an exterior chimney. Insulation keeps flue temperatures up, which improves draft and dramatically reduces creosote formation.
Will relining fix my draft problem?
Often, because a correctly sized liner is one of the biggest factors in draft. An oversized flue lets exhaust cool and stall. Sizing the liner to the appliance usually transforms how the fireplace performs.
Published: July 24, 2026