The liner is the tube inside a chimney that carries smoke and gases out and keeps heat away from the house around it. In most older Eastside masonry chimneys it is a stack of clay tiles; in relined ones, a stainless steel pipe. You rarely see it, which is why the signs of failure are worth knowing before a camera scan confirms them.
What the code expects from a liner
The residential code in force in Washington requires masonry chimneys to be lined, with lining material suited to the appliance connected to it according to that appliance's listing and the manufacturer's instructions. A clay-tile flue built for an open wood fireplace is not automatically right for a gas insert or a modern wood stove.
That is why the Chimney Safety Institute of America recommends a Level 2 inspection, with a video scan of the flue, whenever relining is planned or an appliance is added or swapped for a dissimilar one.
Signs the liner is failing
Some signs show up in the firebox or the room; others only on camera. The table pairs each with what it usually indicates.
| Sign | What it often indicates | How it is confirmed |
|---|---|---|
| Pieces of clay tile in the firebox or smoke shelf | Flue tiles cracking or spalling | Camera scan of the flue |
| Smoke or odor in the room with a good fire | Gaps in the liner or poor draft | Level 2 inspection |
| Water stains or rust on the damper | Moisture getting past the liner | Camera scan plus a look at crown and cap |
| White staining on the chimney breast | Moisture moving through the masonry | Inspection of liner and exterior |
| A new insert or stove on an old flue | Liner may not match the appliance | Check against the appliance listing |
| A strong earthquake since the last inspection | Cracked tiles or offset joints | Level 2 inspection |
Why so many Eastside liners are due
A large share of Eastside housing went up in the decade after the war. HistoryLink records Mercer Island growing from about 1,200 residents in 1940 to nearly 13,000 by 1960, after the floating bridge opened. Clyde Hill's farmland was turning into suburban neighborhoods by the early 1950s, and the City of Bellevue notes that Lake Hills was developed as a planned community in the late 1950s.
Clay flues from that era have now seen roughly seventy winters. Many were also built for open wood fires and have since been fitted with gas logs or inserts, which is exactly the change of use the code and CSIA flag.
What relining involves
Most relining today means running a stainless steel liner, sized to the appliance, from the firebox or insert up to a new top plate and cap. Cast-in-place liners, which coat the inside of the old flue, are another option on some chimneys. The choice depends on the flue's size and shape, the appliance, and what the camera shows.
Permits are part of it when an appliance is involved. In Bellevue, putting in an insert, a zero-clearance unit or a pellet stove needs a permit; Clyde Hill asks for a mechanical permit covering inserts and gas appliances.
| Liner type | Typical use | Note |
|---|---|---|
| Stainless steel, flexible or rigid | Inserts, stoves, gas appliances, damaged clay flues | Sized to the appliance outlet |
| Cast-in-place | Sealing and resurfacing an existing masonry flue | Depends on flue condition |
| Clay tile (original) | Open wood fireplaces as built | Replaced only in a rebuild |
What it runs
Our relining starts at $1,895, and the written quote is set by the length of the flue, the liner type and the appliance it serves. The on-site inspection is $99 plus tax, and it is credited toward the work when you approve the written quote.
We did not find a published Eastside or Seattle relining figure we could cite, so we do not print a local market range. For national context only, Fixr puts a stainless liner installation at $1,800 to $4,000 per flue, and Rockford Chimney Supply cites $2,500 to $7,000 for professional relining of traditional fireplaces. Neither is an Eastside number, and neither is our quote.
Frequently asked questions
How do I know if my chimney liner is cracked?
Tile fragments in the firebox, smoke or odor with a good fire, and rust on the damper are common clues. Only a camera scan of the flue confirms it.
Do I need a new liner for a fireplace insert?
The liner has to suit the appliance according to its listing and manufacturer's instructions. An insert on an old clay flue usually gets its own stainless liner, and Bellevue requires a permit for insert installation.
Is it safe to use a fireplace with a damaged liner?
No. The liner keeps heat and gases away from the framing around the chimney. Have it inspected before the next fire.
What inspection do I need before relining?
CSIA recommends a Level 2 inspection, which includes a video scan of the whole flue, whenever relining is planned.
Sources
- UpCodes — WA Residential Code, ch. 10 (chimneys) — accessed September 23, 2026
- CSIA — Level 2 inspection SOP (masonry fireplace) — accessed September 23, 2026
- HistoryLink — Mercer Island incorporates (1960) — accessed September 23, 2026
- City of Clyde Hill — History — accessed September 23, 2026
- City of Bellevue — Neighborhood Profiles — accessed September 23, 2026
- City of Bellevue — Work Requiring Permits — accessed September 23, 2026
- City of Clyde Hill — Mechanical Permit — accessed September 23, 2026
- Fixr — Chimney liner installation cost — accessed September 23, 2026
- Rockford Chimney Supply — Cost to line a chimney — accessed September 23, 2026
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