Chimney and fireplace symptoms
My chimney is leaning and there is a gap where it meets the house
A Portland chimney that leans or pulls away from the siding has often lost the mortar in the stack above the roof, sometimes its footing. Stop using the fireplace until a Level 2 inspection, and treat the ground below as a fall zone.
Updated
What to do right now
Do not light a fire, and keep people, pets and parked cars out of the strip of ground the chimney would land on if it came down. If brick is falling right now, keep everyone back and call 911. After a quake or windstorm, send us photos of the lean and the gap taken from the ground.
Likely causes, most common first
A lean starts at the footing or at the roofline, and the shape of the gap at the siding tells us which.
- Most common
The mortar above the roof has failed and the stack is rotating
The sign: The lean begins at the roofline, the gap at the siding is a wedge widest at the top, and the joints on the weather face are open.
The fix: The brick above the roof is dismantled to sound courses and rebuilt plumb, with a new crown and new flashing. Chimney Rebuild, from $2499
- Common
The footing has settled or washed out
The sign: The whole stack tilts from the ground up, the gap is even or widest at the bottom, and sunken soil or a foundation crack at the base shows movement.
The fix: A Level 2 inspection traces the lean to the footing from the basement or crawl space, and the footing is stabilized before any brick is relaid. Chimney Inspection, from $129
- Common
The chimney has drifted from the house but still stands plumb
The sign: A narrow, even gap along the whole height, old caulk in it, stretched flashing, and no tilt when you sight up the corner.
The fix: Once the inspection confirms the stack is stable, the open joints are repointed and the gap is flashed and sealed against the weather. Tuckpointing and Masonry Repair, from $449
- Less common
An earthquake or a windstorm moved it
The sign: A lean or a gap that was not there before the event, a horizontal crack at the roofline or the shoulder, and brick or mortar on the roof.
The fix: A Level 2 inspection, which becomes a Level 3 if the damage runs into the framing, decides between a rebuild and lowering the stack to the roofline. Chimney Inspection, from $129
Two minutes of safe checks
Everything here happens at street level, from the basement or through the attic hatch, with no hand on the chimney.
- Stand across the street and sight up the corner of the chimney against the corner of the house; a lean you can see from there is well past hairline.
- Study the gap at the siding: a wedge widest at the top means the stack is rotating from the roofline; an even gap, or one widest at the bottom, means the footing.
- Walk around the base: sunken soil, a cracked foundation wall or a downspout emptying beside the chimney all point to the footing.
- Check the ground and the gutter below for fresh brick chips, mortar or cracked sealant; fresh pieces mean the stack is still moving.
Why old Portland chimneys lean: unreinforced brick standing on its own
Old Portland chimneys lean because many are freestanding columns of unreinforced brick on their own footings, often held to the house by little more than flashing. House and stack move at different rates, and the gap shows it.
The stack above the roof is the thinnest, most exposed part of the chimney, with the least holding it up and the most wind and rain working on it. Once the joints up there open, the weight of the top courses pushes toward the softened side, and the lean feeds on itself.
Portland's unreinforced masonry program covers buildings, not house chimneys, but a house chimney is the same brick and mortar and it fails the same way in shaking. The State of Oregon puts the odds of a magnitude 7.1 or larger Cascadia earthquake in the next fifty years at about 37 percent, and tall, slender chimneys are the most vulnerable.
What a Level 2 inspection looks for, and when it becomes a Level 3
On a leaning chimney, a Level 2 uses a camera in the flue and a look through the attic, crawl space and exterior to find cracked or displaced tiles, a gap running into the framing and a footing that moved.
Under the inspection levels defined in NFPA 211, a Level 2 is the one the trade uses after an event such as an earthquake or storm, and a lean is that kind of damage. The camera looks for open joints between tiles and offsets where the flue no longer lines up; the attic shows whether clearance to wood has closed, and the basement shows the footing.
A Level 3 follows only when a hidden hazard is suspected and the one way to see it is to open something: siding, a section of wall, the back of the firebox. You hear why before anything is opened.
What the fix involves once the inspection is in
The repair follows the finding, and these are the usual outcomes.
| What the inspection finds | What follows |
|---|---|
| A plumb stack with a weathered gap | The open joints are repointed, the gap is flashed and sealed, and the chimney is photographed so the gap can be compared next year. |
| A lean that starts at the roofline | The brick above the roof is taken down to sound courses and relaid plumb, with new flue tiles where they cracked, a new crown and new flashing. |
| A settled footing | The footing is stabilized first, which is foundation work, and the chimney is rebuilt on it afterward, because a stack relaid on a moving footing leans again. |
| A stack not worth saving | The upper chimney comes down and a listed metal chimney goes up inside a framed, braced chase, one of the retrofits in FEMA's chimney plan set. |
| A sound stack you want braced for a quake | Straps and roof plywood reduce the danger of falling brick, and FEMA says plainly its details may not prevent damage or collapse. Bracing lowers a hazard; it does not fix a lean. |
Leaning chimney: common questions
Is a chimney leaning away from the house about to fall?
Treat it as if it could, and let the inspection say otherwise. Many leaning chimneys have moved slowly for years, but nobody can tell a slow lean from a fast one from the sidewalk. Keep the fall line clear, skip the fires, and get photos to us the same day.
Is a small gap between the chimney and the house normal, or is the chimney pulling away?
A hairline gap is common, because a masonry chimney and a wood-framed house are separate structures that move with the seasons. A gap you can slide a finger into, one wider at the top than the bottom, or one that has grown since it was last caulked is the chimney pulling away, and it gets a Level 2 inspection.
Can a leaning chimney be straightened, or does it have to be rebuilt?
Brick cannot be pushed back plumb; the part that leans is taken down and relaid. When the lean starts at the roofline, that means the stack above the roof, which is a partial rebuild. When the footing has moved, the footing is repaired first and the chimney is rebuilt on it. A plumb stack with a gap needs repointing and flashing only.
Should I call a foundation company or a chimney company about a chimney that is leaning?
Start with the chimney inspection, because it tells you which one you need. A lean that begins at the roofline is masonry work from start to finish. A lean from the ground up points at the footing, and the Level 2 report gives a foundation contractor the measurements and photos to work from before we rebuild the stack.
Can I use the fireplace while the chimney is leaning if I keep the fire small?
No. A lean often cracks or shifts the flue tiles inside, and even a small fire puts hot gas against whatever sits behind those cracks, which in an old house can be wood framing. The fireplace stays cold until the camera run shows an unbroken flue, and the repair comes before the next fire.
Related pages
Areas we cover for this
Calls about leaning chimney come in from Hazelwood and Mill Park, Milwaukie, Raleigh Hills and Garden Home and every other part of the metro we serve.
Ready to book a sweep?
Call with what the fireplace is doing, or text a photo of the opening and one of the chimney top, and we will name the service and its posted price before we come out.