Chimney Relining for Wood Fireplaces, Stoves and Inserts

The flue liner is the part of a chimney nobody sees and the part that keeps heat and smoke away from the wood framing around the stack. The current Minnesota Residential Code is direct about it: masonry chimneys shall be lined, and the lining has to suit the appliance connected to it (IRC R1003.11). Many prewar chimneys in Minneapolis and St. Paul were built with no liner at all, and many later ones have clay tiles that have cracked from a chimney fire or from decades of freezing and thawing.

This page covers liners for wood-burning fireplaces, wood and pellet stoves and inserts. If the flue serves a gas furnace or water heater, Minnesota has its own metal-liner rule, explained on our furnace and water heater liner page. In both cases the free inspection includes a look up the flue, and a camera scan when a hidden problem is suspected is priced at the inspection.

Signs you need this

• Pieces of clay tile in the firebox or on the smoke shelf
• A camera or flashlight shows gaps between tiles or missing mortar joints
• A past chimney fire, even a small one
• You plan to put a wood stove or insert into a fireplace
• Smoke or smell showing up in a room the chimney passes through

How we do it

1. Look inside, freeWe check the flue from the top and the firebox and photograph what we see. If the damage is hidden, a camera scan is priced at the inspection.
2. Match the liner to the applianceStainless for stoves, inserts and most fireplaces; cast-in-place when the old flue is irregular or the masonry needs strengthening.
3. Check what your city requiresSeveral metro cities list chimney liners as mechanical permit work. We check what your city requires before scheduling.
4. Install and insulate where neededThe liner runs the full height, with insulation where the clearances or the listing call for it, and is sealed at the top under a cap.
5. Test and photographWe check the draft with a fire or the appliance running and leave you photos of the finished flue.

Stainless or cast-in-place

A stainless steel liner is a round flexible or rigid pipe dropped down the existing flue and connected to the stove, insert or fireplace below. It is the common choice for a stove or insert in a masonry chimney, because it gives the appliance a continuous, correctly sized flue. National 2026 guides put it at $900 to $3,800 installed.

A cast-in-place liner is a heat-resistant mix poured or pumped around a form inside the old flue. It fills gaps, follows a crooked flue and adds strength to old masonry, which can make sense in a tall prewar chimney with shifted bricks. It typically runs $2,000 to $7,000.

Code points we build to

These come from the current Minnesota Residential Code, which adopts IRC chapter 10 as mandatory statewide:

• Masonry chimneys shall be lined, suited to the appliance (R1003.11)
• A clay flue lining starts at least 8 inches below the lowest inlet and runs up past the enclosing walls (R1003.12)
• The space around a liner may not be used to vent another appliance (R1003.12.2)
• The flue may not be smaller than the appliance connector (R1003.14)

Why so many old metro flues need it

Freeze-thaw is hard on clay tile and the mortar between the tiles. By our count from NOAA's 1991–2020 normals, the airport sees roughly 75 days a year that freeze at night and thaw by day, and the colder north metro roughly 90. Water that gets past a missing cap or a cracked crown soaks the top tiles and splits them. Inside, condensation from a slow, smoky fire does the same from the other side. When the clay is too damaged to repair, a new liner is the fix.