Chimney Masonry Repair · Bothell, WA
Repointing and spalled brick on a Bothell chimney
Mortar joints are the sacrificial part of masonry by design — they give way before the brick does — so some erosion on a chimney is the system working. The question is whether yours has gone past that, and what has been feeding it.
On a Bothell chimney the answer usually has more to do with how much water the stack takes than with how the mortar was mixed fifty years ago.
Reviewed by Chimney4u editorial team · Last updated
What fifty wet winters do to a Bothell stack
On the King County side of the city, the assessor puts the typical home in several sub-areas in the mid-to-late 1970s. A chimney of that vintage has now stood through about fifty winters in a climate that delivers roughly 39.34 inches of precipitation a year, about three quarters of it between October and March.
The damage mechanism here is not a hard freeze. It is saturation followed by a shallow overnight freeze and a thaw by mid-morning, repeated. Masonry carrying too much water spalls, crazes, and cracks through that cycling, and the joints go first because they are softer than the brick and because they are where water is already travelling.
Matching mortar to what is actually up there
The single most consequential decision in a repointing job is the mortar, and the rule runs the opposite way to intuition. Repointing mortar has to be equal to or lower in compressive strength than the original, because stronger mortar concentrates stress at the brick-mortar interface and spalls the face off the brick. The masonry industry's own selection rule is to choose the lowest-strength mortar that meets the requirement — stronger is not better, it is just harder to undo.
The year on the property record does not settle this. A 1970s chimney is not a historic lime-mortar building, and the advice a homeowner finds online for one is frequently written for the other. What the mortar has to match is what is in the wall, established at the wall.
Spalled brick, and what a replacement has to be
Spalling is the brick face flaking, popping, or crumbling away, and it happens when saturated brick freezes. A brick used where it will be wet and freezing has to meet the severe weathering grade, demonstrated by passing 50 freeze-thaw cycles or by limits on strength, absorption, and saturation coefficient. That is the specification a replacement brick on a Bothell chimney should be held to, not simply a colour match.
Landmark review and permits in Bothell
Bothell has a Landmark Preservation Board and its own Bothell Register of Historic Landmarks, so an older downtown or Main Street property can carry review obligations that a postwar tract house does not. Repointing changes the appearance of an exterior wall — colour, texture, and joint profile all shift — which is exactly the kind of alteration a landmark process cares about.
The permit question is separate and citywide. Applications go to the City of Bothell Permit Center on both sides of the county line, and Bothell adopts the International Residential Code through Title 20 of its municipal code, which reaches alteration and repair of dwellings. Note that Seattle's published guidance about repointing not needing a permit where no structural change is made is Seattle's guidance for Seattle addresses; it is not a statement about Bothell.
Local considerations in Bothell
- Several sub-areas on the King County side of the city have a typical home dating to the mid-to-late 1970s on the assessor's own reckoning, which puts a great many Bothell chimneys at roughly fifty years of weather exposure.
- Sea-Tac averages 39.34 inches of precipitation a year, with about three quarters of the annual total falling between October and March. Masonry that carries too much water spalls, crazes, and cracks through repeated freeze-thaw cycling, and the local pattern is saturation plus shallow overnight freezing rather than a deep freeze.
- Repointing mortar has to be equal to or lower in compressive strength than the original, and the industry selection rule is the lowest-strength mortar that meets the requirement. A build year does not settle what that mortar is; the existing wall does.
- Brick used where it will be wet and freezing must meet the severe weathering grade, demonstrated by passing 50 freeze-thaw cycles or by strength, absorption, and saturation-coefficient limits. That is the standard a replacement brick on a Bothell chimney should meet.
- Bothell has a Landmark Preservation Board and a Bothell Register of Historic Landmarks, so exterior masonry work on a listed downtown or Main Street property can carry review obligations that a tract house does not.
- One counter serves the whole city: permit applications for any Bothell address go to the City of Bothell Permit Center, under the building code the city adopts in Title 20, which reaches alteration and repair. Seattle's published guidance that repointing needs no permit absent structural change describes Seattle, not Bothell.
What the job includes
- A close look at the joints where access allows, including a light scrape to find where sound mortar begins, and at the crown, cap, and flashing above them, because those are usually why the joints failed
- A written scope and price before anything is opened up, naming the areas, the cut-back depth, and the mortar type
- Removal of deteriorated mortar to a uniform depth of at least twice the joint width, with head joints chiselled by hand rather than ground
- Mortar no stronger than what is already in the wall, packed in thin lifts and tooled at thumbprint hardness to a profile that sheds water
- Cut-out and replacement of individual spalled bricks with a replacement rated for wet, freezing exposure, shown to you before it goes into the wall
- Photographs of the same joints before and after, from the same angles where practical
What it does not include
- Crown, cap, and flashing work. Those are separate scopes even though they are frequently the reason the joints below them failed
- Anything inside the flue: sweeping, camera scanning, or relining. Repointing addresses the outside of the chimney only
- Water repellent, which only makes sense once the masonry is sound and dry, and which is a different service
- Rebuilding a section of the stack, or any work needing engineered design. Where the signs point to movement rather than weathering, that assessment belongs to a structural engineer
- Submissions to Bothell's landmark review process. Where a property is on the city's register, that process runs through the city
- Any determination of what your project needs under the code Bothell has adopted
What to look for
- Brick chips and orange grit on the roof or in the gutter after a cold snap
- That is the brick face coming off, not surface dirt. Spalling after a freeze means the brick was saturated when the temperature dropped, and it will continue as long as it keeps getting wet.
- The brick face sounds hollow when you tap it
- The face is delaminating from the body of the brick. It has not fallen off yet, but it is no longer bonded, and repointing around it does not put it back.
- Only one face of the chimney is deteriorating
- That is the weather face. Driven rain arrives from one quarter, and a stack in an exposed position takes far more of it on one side, which is why repointing is often scoped by face rather than all round.
- The pointing looks fresh but sits proud of the brick face
- Somebody has smeared new mortar over unsound joints instead of cutting them back. It is bridging rather than bonded, and the deterioration underneath has continued since.
- The chimney has been painted or sealed at some point
- A non-permeable coating traps moisture behind it and speeds decay up. Damage under a painted chimney is usually further along than the outside suggests.
What changes the price
We do not publish a headline figure, because it would be a guess about your chimney. These are the things that genuinely move the number, and we put a real one in writing after we have looked.
- How much of the stack needs work
- Spot repointing on one exposed face is a different job from cutting back every joint above the roofline, and the deciding factor is usually how long water has been getting in.
- Access and height
- Pitch, surface, and the chimney's position on the roof set the equipment and the time. Ridge lots in the higher neighbourhoods are often steeper than the street frontage suggests.
- Whether the water source has to be corrected first
- New mortar in joints that are still being fed by a cracked crown or a failed flashing detail is a temporary repair, so the crown and flashing usually have to be in the same scope.
- Brick matching and replacement
- Individual spalled bricks have to be cut out and replaced with a brick rated for wet, freezing exposure that also matches in size and appearance, and the second condition is often harder to meet than the first.
- Landmark or permit review
- Where the property carries landmark obligations, or where the scope crosses a permit threshold, the review time belongs in the schedule.
- Season and working temperature
- Mortar needs a dry substrate and workable temperatures to cure properly, so a repointing job in the wet half of the year loses working days to the forecast.
Chimney Masonry Repair in Bothell — common questions
- My Bothell chimney is from the 1970s. Does it need a historic lime mortar?
- Almost certainly not, and the decade is the wrong thing to reason from. The rule is that repointing mortar must be equal to or lower in compressive strength than the original, and that the lowest-strength mortar meeting the requirement is the right one. Plenty of chimneys in this city date to the 1970s, but what matters is what is in your wall, matched at the wall rather than from a build year.
- Do I need a permit to repoint a chimney in Bothell?
- Ask the City of Bothell Permit Center, which handles applications for the whole city on both sides of the county line, and get the answer in writing. Bothell adopts the International Residential Code through Title 20 of its municipal code, which reaches alteration and repair of dwellings. Seattle publishes guidance that repointing needs no permit where no structural change is made, but that is Seattle's guidance for Seattle addresses and is not a statement about Bothell.
- My house is on Bothell's landmark register. Does that change the repointing?
- It can change the process and the specification. Bothell has a Landmark Preservation Board and a Bothell Register of Historic Landmarks, and repointing alters the appearance of an exterior wall — mortar colour, texture, and joint profile all shift. Ask the city what review applies to your property before any joint is cut back, because that answer can determine the mortar and the tooling as well as the paperwork.
- Would a water repellent have prevented this in a climate this wet?
- Not on its own, and applied at the wrong moment it makes things worse. Sealing spalling masonry with waterproofing or non-permeable paint traps moisture behind the coating and speeds the decay up, and film-forming coatings are specifically advised against on brickwork in freeze-thaw environments. With about 39.34 inches of precipitation a year, anything applied here has to let the wall dry — penetrating, vapour-permeable, and only after the masonry is sound.
- The fireplace has not been used in years. Is repointing worth doing?
- The masonry deteriorates on the same schedule whether or not you light fires in it, because the damage is water and freezing rather than heat. An unused chimney that collects rainwater should get a ventilated cap as part of controlling moisture in the building — ventilated so the shaft can still dry rather than sealed shut. If the stack is staying on the house, it still has to shed water.
Sources
- Bothell / East Kenmore, Area 038 Area Information Report (2024 revalue) — King County Department of Assessments. Accessed 2026-08-27.
- Landmark Preservation Board — City of Bothell. Accessed 2026-08-27.
- Permit Center — City of Bothell, Community Development Department. Accessed 2026-08-27.
- Bothell Municipal Code Title 20, Buildings and Construction, Chapter 20.04 Building Regulations and International Codes — City of Bothell / Code Publishing. Accessed 2026-08-27.
- U.S. Annual/Seasonal Climate Normals 1991-2020, station USW00024233 — NOAA National Centers for Environmental Information (NCEI). Accessed 2026-08-27.
- U.S. Annual/Seasonal Climate Normals 1991-2020, station USW00024233 (seasonal precipitation) — NOAA National Centers for Environmental Information (NCEI). Accessed 2026-08-27.
- Technical Notes on Brick Construction 46 - Maintenance of Brick Masonry — Brick Industry Association, December 2017. Accessed 2026-08-27.
- Technical Notes on Brick Construction 8B - Mortars for Brickwork: Selection and Quality Assurance — Brick Industry Association, March 2020. Accessed 2026-08-27.
- Technical Notes on Brick Construction 7B - Water Penetration Resistance: Construction and Workmanship — Brick Industry Association, November 2017. Accessed 2026-08-27.
- Technical Notes on Brick Construction 9B - Manufacturing, Classification and Selection of Brick: Selection, Part 3 — Brick Industry Association. Accessed 2026-08-27.
- Technical Notes 6A - Colorless Coatings for Brick Masonry — Brick Industry Association. Accessed 2026-08-27.
- Preservation Briefs 2: Repointing Mortar Joints in Historic Masonry Buildings — U.S. National Park Service, Heritage Preservation Services (Robert C. Mack, FAIA and John P. Speweik), October 1998, ISSN 0885-7016. Accessed 2026-08-27.
- Common Problems with Brick Masonry — U.S. National Park Service (originally published 2008; page states last updated June 29, 2018). Accessed 2026-08-27.
- Preservation Briefs 39: Holding the Line - Controlling Unwanted Moisture in Historic Buildings — U.S. National Park Service, Heritage Preservation Services (Sharon C. Park, AIA). Accessed 2026-08-27.
- ChimneySaver Professional Water Repellent (with companion pages: /products/300190, /products/300511, /pages/read-the-label-water-repellent-with-stain-blocker) — SaverSystems / ChimneySaver. Accessed 2026-08-27.
- House Additions & Remodels — Seattle Department of Construction and Inspections (SDCI). Accessed 2026-08-27.
Next step
Start with an inspection
Tell us what you have noticed. We will look at the chimney, show you what we found, and put a price on the work before anything begins.