Chimney Relining in Seattle: What the Appliance, the Flue and the Liner Decide

Seattle enforces the 2021 Seattle Residential Code, and its chimney chapter is brief on the subject. Section R1003.11 says a masonry chimney is to be lined in a way that suits the appliance connected to it. Three routes satisfy the section: clay flue tile made to ASTM C315, a listed lining system tested to UL 1777, or another approved material that stands up to corrosion and to heat as high as 1,800°F.

Two practical points follow. The liner is matched to the appliance, so a flue that was right for an open fireplace is not automatically right for an insert, a stove or a gas unit. And the city's mechanical code, in section 905.1, requires a fireplace insert to carry a UL 1482 listing and label and to be installed the way its maker directs. The installation manual of the unit you buy is therefore part of the specification, and we read it before sizing anything.

The appliance. An open wood fireplace, a wood insert, a gas insert and a furnace each send different heat and different exhaust up the flue. Liner diameter and liner material follow from that.

The run. A liner is bought by length and lowered in from the roof. Two stories of stack take more material than one, an offset calls for a flexible liner and extra labor, and a steep or high roof adds setup time. A stack that holds two flues may need two liners.

The condition found. Loose tile fragments, hard glazed creosote or a failed crown have to be dealt with before new metal goes in. That preparation appears as its own line on the quote so you can see what it is.

One Seattle company prints the two local lines in the table, and the national line comes from Fixr. They are other publishers' numbers, collected on October 4, 2026. Not our quote.

Our own relining starts at $1,900, and the top of our grid is $5,900. The lower part of that span is a short, straight flue under a roof that can be walked. The upper part is a tall stack, an offset, an insulated liner or a second flue inside the same chimney.

Age is the best public clue to what a flue has lived through, and housing age shifts a great deal across a few miles of North Seattle. The 2020-2024 American Community Survey counts 36.3 percent of the housing units in ZIP area 98117, which lies to the north and west of Ballard's core, as built in 1939 or earlier. In 98103, the ZIP area where Green Lake, Phinney Ridge, Wallingford, Fremont and the southern blocks of Greenwood meet, the share is 34.7 percent. In 98125, which takes in Northgate, it drops to 7.6 percent and the median year built is 1974. Seattle as a whole stands at 22.8 percent.

Those are counts by decade for ZIP areas, not for neighborhoods, and no public source we found says what kind of chimney any of those homes has. What the counts do show is how likely it is that a flue near you has been in service for eighty years or more, through several changes of appliance.

Heating fuel is the second clue. The same survey finds fuel oil still heating 7.9 percent of homes in 98117, 5.8 percent in 98115 (the ZIP area spanning Ravenna, Wedgwood and Maple Leaf) and 4.7 percent in 98125. When an oil furnace is retired, the flue it vented through ends up serving a different appliance or none at all, and that is one of the moments the liner question comes up.

Seattle's Department of Construction and Inspections rates the chance of a damaging earthquake in the city at 86 percent over a 50-year horizon. In its guidance on masonry chimneys, FEMA identifies the kind most exposed: old unreinforced brick whose mortar has weakened. It adds that masonry chimneys built to modern code can suffer significant damage as well.

A flue can crack in a quake while the stack outside looks unmoved. For a chimney that has been damaged, FEMA advises against putting it back exactly as it was, and one of the options it describes is a metal flue run inside a lightly framed enclosure that rises from the top of the firebox. FEMA wrote that advisory after a California earthquake, so take it as general guidance on how chimneys behave and not as a Seattle study.

We do not print a blanket answer on permits for relining, because the city does not print one. What SDCI's permit guide does say is that most projects beyond its short exemption list need a permit, and fireplace, furnace, gas and mechanical work are all named in that sentence. Repointing a chimney is on the exempt list by name.

Timing matters when a permit applies. For a standard mechanical permit SDCI quotes roughly 9 weeks, counted from the application. Simple jobs, it says, may qualify for a permit issued subject to field inspection inside 24 hours. Either way the application is filed through the Seattle Services Portal. We check with SDCI for your address and your appliance before work starts, and the answer goes into the written quote.

Nobody can size a liner from the hearth. The visit comes first: $99 plus tax per chimney, with the camera run through the flue when its condition calls for it. You receive the findings and a written quote. If you approve the relining, the $99 is deducted from that bill.