St. Anne wood stove vented into an oversized clay flue: why we relined it to stainless
A St. Anne homeowner put a modern wood stove in the old farmhouse fireplace and ran the pipe straight up into the original clay-tile flue. The stove ran lazy and the chimney loaded with creosote fast. The flue was simply too big for it.
A big flue is the wrong flue for a stove
It seems backward, but a wood stove does not want a large chimney. A modern stove produces a small, controlled volume of exhaust. Send that into a wide 8×12 clay flue built for an open fireplace and the exhaust spreads out, slows down, and cools. Cool, slow exhaust drops its moisture and tar on the tile walls — that is creosote — and the stove never develops a strong draft. This St. Anne farmhouse had both problems: sluggish fires and a flue glazing over within a single season.
The old clay tiles were also cracked at a couple of joints, common in the century-old chimneys out here. A wood stove that connects to a flue with no proper liner is exactly the kind of install we see cause chimney fires.
Matching the liner to the appliance
The fix is an insulated stainless steel liner sized to the stove’s flue collar — typically six inches for a stove like this. Dropping the flue down to the right diameter speeds the exhaust back up so it stays hot and carries its moisture out the top instead of condensing on the way. The insulation keeps the liner warm, which is what keeps draft strong and creosote buildup slow.
Our liners are listed to UL 1777, and we install to the NFPA 211 standard, with the connector pipe and the liner sized to what the stove manufacturer calls for. That combination is what turns a lazy, dirty setup into a clean, drafting one.
What the homeowner noticed afterward
With the right-sized insulated liner, the stove lit faster, held a cleaner burn, and used less wood for the same heat. The annual sweep came back with light, dry soot instead of the hard glaze we found the first time. [Observed] An oversized, uninsulated flue serving a stove is the single most common cause of fast creosote loading we see on these conversions.
If you have added a stove or insert to an old fireplace and it never drafted right, the flue size is the first thing to check. Our relining pricing is published, and we can camera-scan the existing flue before we quote.
If this sounds like your house: we handle chimney relining across Kankakee County, and our St. Anne page covers what we usually find there. Call (815) 449-4264, 7am to 9pm, any day.
Quick questions
Why does my wood stove need a smaller flue than my fireplace had?
A stove makes a small, cooler volume of exhaust. A large fireplace flue lets it spread out and cool, which kills draft and builds creosote. A right-sized insulated liner keeps the exhaust fast and hot.
What size liner does a wood stove need?
Usually the diameter of the stove’s flue collar — six inches on most stoves. We match the liner to what the manufacturer specifies rather than reusing the big fireplace flue.
Is it dangerous to run a stove into an unlined clay flue?
It can be. If the clay is cracked or oversized, the stove drafts poorly and loads creosote quickly, which raises chimney-fire risk. A liner listed to UL 1777 corrects both.
Will relining really cut down on creosote?
In our experience, yes — dramatically. An insulated, correctly sized liner keeps exhaust warm so it carries moisture and tar out the top instead of depositing it on the walls.
Published November 6, 2026 · By Jacob Dove, Friendship Chimney Sweep, Bourbonnais IL