Crumbling mortar and spalling brick on an Everett chimney

Two numbers from the same weather station tell the whole story. The Everett and Snohomish County Airport station normally records 21.4 nights a year with a minimum at or below freezing, but only 1.7 days a year with a maximum at or below freezing.

Read them together and you get the local mechanism. Masonry here does not go cold in December and stay cold. It freezes overnight and thaws by the following afternoon, roughly twenty times a winter. Each of those is a separate expansion event inside saturated pores, and it is the count of cycles, not the depth of the cold, that opens joints, lifts crown edges, and pops brick faces.

The masonry is wet when it happens, which is the other half of it. Brick and mortar are networks of microscopic capillaries that draw water in by suction and then dry themselves by evaporation, and damage begins when the masonry stops fully drying between wettings. Everett's seasonal normals put 12.66 inches of precipitation across December through February against 4.05 across June through August, so the cycling season and the saturated season are the same season.

One more factor belongs on a chimney specifically. Heavy wind-driven rain will penetrate a single wythe of brickwork no matter how good the materials or the workmanship, and a chimney above the roof line is exposed on all four sides with no interior behind it to help it dry. On the water side of Everett, where about 25 miles of the city's edge is shoreline, that exposure is not theoretical.

As of 2023 more than 7,200 Everett housing units dated from 1939 or earlier, and about half of all housing in the city predated 1980. That makes the common Everett repointing job a job on masonry laid with a softer, more lime-rich mortar than anything sold today as a general-purpose mix — which turns the industry's mortar rules from good practice into the difference between a repair and a slow demolition.

• The repointing rule. Repointing mortar must be equal to or lower in compressive strength than the original mortar. A stronger mortar does not fail gracefully: it concentrates stress at the brick and mortar interface and spalls the face off the brick instead of giving way itself.
• The selection rule. The masonry industry's own rule is to choose the mortar type with the lowest compressive strength that meets the project's requirements. Stronger is not better, and on eighty-year-old brick it is actively worse.
• Hardness and permeability are different properties. A dense, hard mortar also passes less water vapor, so it pushes drying out of the joint and into the brick — the one part of the assembly you cannot replace cheaply.
• Replacement brick has a grade. Brick used where it will be wet and freezing must meet the severe weathering grade, demonstrated by passing 50 freeze-thaw cycles or by meeting strength, absorption, and saturation-coefficient limits. In a city running about twenty cycles a winter that is the grade that matters, and it is worth naming in the written scope.

The joint finish is not cosmetic either. Concave, V, and grapevine profiles resist water penetration best on exterior brickwork, and the joint has to be tooled at thumbprint hardness so the mortar is compacted against the brick rather than merely smoothed. On a chimney taking wind-driven rain off Port Gardner, that detail is doing real work.

Repointing is the chimney repair most likely to change how a house looks. Mortar color, joint width, and joint profile are all visible from the sidewalk, and on a house whose brickwork is original, a repointing done in the wrong color or the wrong profile is the thing everyone notices afterward.

In parts of Everett that is not only an aesthetic question. The city has three historic overlay zones — Rucker-Grand, Norton-Grand, and Riverside — with adopted Neighborhood Conservation Guidelines and Historic Zoning Overlay Standards. Separately, a property listed on the Everett Register of Historic Places obligates its owner to consult the Historical Commission before major work and obtain a Certificate of Appropriateness.

The good news is that the preservation answer and the water answer usually point the same way. The original profile on brickwork of this age is very often concave or V, which is also what resists water penetration best, and the rule that new mortar must be no stronger than the original is the same rule preservation practice has applied to historic masonry for decades. What matters is that the mortar type, the color, the joint width, and the profile are decided and written down before the first joint is cut back, because after that the comparison sample is gone.

Repointing restores the weather surface of the masonry. It does not add structural capacity, it does not straighten anything, and it is not a way to replace brick in bulk. Three findings move an Everett stack out of this scope.

• The proportion tips. Once most of the joints across a face need cutting back rather than a band of them, the labor curve crosses the rebuild curve and you are paying repointing prices for a rebuild's worth of work without getting a rebuild.
• The damage has moved into the brick. Joints can be replaced. Brick faces that have spalled off across a whole elevation cannot be patched back, and individual cut-and-replace stops making sense past a certain count.
• It is movement, not weathering. Stepped or diagonal cracking, cracks running through bricks rather than around them, or a stack out of plumb. That is a structural question, and the assessment belongs to a structural engineer before any masonry quote is written.

There is also a sequencing rule that catches people out on older Everett chimneys. If the crown has failed, or the cap or chase cover has corroded through, or the flashing is open, the water arriving in those joints has a source above them. New mortar packed under an open source is a repair with a date on it. Close the source first, then repoint.