Chimney liners and relining
The liner is what keeps heat, smoke and exhaust inside the chimney. Older Duluth chimneys often need one replaced or added.
A flue liner is the inner channel that carries smoke or exhaust up and out. In most older homes it's clay tile set in the chimney when it was built. Some very old chimneys have no liner at all. Liners crack from age, from a chimney fire, or from acidic moisture when the appliance using them changes.
When does a chimney need relining?
- An inspection camera shows cracked, shifted or missing flue tiles
- Pieces of tile turn up in the firebox, cleanout or at the base of the flue
- The chimney has had a chimney fire
- The flue is unlined
- You're installing a new furnace, boiler, water heater or wood stove that needs a correctly sized flue
Why do new furnaces cause liner problems?
Older furnaces sent a lot of hot exhaust up a big masonry flue. Newer, more efficient appliances send cooler exhaust that can condense inside an oversized flue, and that moisture is acidic. Over time it eats at clay tile and mortar from the inside, often showing up as white staining on the outside of the chimney. A liner sized for the new appliance keeps exhaust warm enough to vent properly. Some high-efficiency furnaces don't use the chimney at all and vent through the wall, which can leave a water heater alone in an oversized flue. Ask the installer how each appliance will vent.
What types of liners are there?
- Stainless steel liners, rigid or flexible, are the most common retrofit for wood stoves, inserts, furnaces and boilers. They're often insulated.
- Cast-in-place liners pour a cement-based lining inside the old flue.
- New clay tile is mostly used when a chimney is being rebuilt.
The liner should be listed for the fuel and appliance it serves and installed to the maker's instructions. New appliances and relining for them often need a permit. In Duluth that goes through Construction Services and Inspections.
The chimney company prices the job after seeing the chimney, usually from the roof and inside the flue. We don't quote prices, and any figure given over the phone before an inspection is only a rough starting point.
Where we connect you with help
Common questions
Do I need a liner for a wood stove insert?
Inserts are typically installed with a stainless liner running the full height of the chimney. Check the insert maker's instructions and ask the installer.
Can I still use my fireplace with a cracked flue tile?
It isn't safe to assume so. Cracks can let heat and gases reach the house framing. Have the chimney inspected before using it.
Related services
- Chimney masonry and tuckpointing
- Chimney crowns and caps
- Chimney leak repair
- Chimney inspection and sweeping
More background: Duluth chimney guide.
Loose brick, a leaking chimney or a stove you haven't had checked?
Call now and a local chimney company will look at it and quote the work.