Sandy · Salt Lake County
Masonry Repair on Sandy Chimneys
Brick does not fail because it is old. It fails because water got inside it and then froze, and on the Sandy bench that happens more times per winter than most owners would guess.
Freeze-thaw is the whole mechanism
A chimney is the one part of a house with masonry exposed on all four sides, nothing over the top of it, and no heat behind it once the fire dies. Rain and melting snow soak into the mortar joints and the outer face of the brick. When the temperature drops below freezing, that water expands and pushes the brick apart from within. One cycle does nothing at all. A few hundred cycles takes the face off the brick.
The east side of Sandy runs colder at night than the valley floor and then warms in afternoon sun, so a single week in February can deliver several complete freeze-thaw cycles instead of one. South and west faces get sun and dry out quickly. North faces stay shaded and frozen, then soak up the next storm. That is why damage on a bench chimney is so often lopsided, with one face crumbling while the opposite face looks nearly new.
The crown is where it starts
The crown is the concrete slab at the top that throws water clear of the flue. Most were built too thin, poured flat instead of sloped, and cast tight against the flue tile with no expansion joint. The tile moves with heat, the crown does not, and a crack opens between them. From that moment the crown has stopped being a roof and started being a funnel, feeding water down inside the brickwork where nobody sees it until mortar joints lower down begin washing out.
Order of work matters. Sealing a crack in a crown that is already saturated traps the water instead of shedding it. We cut the crown back to sound material, rebuild it with a real overhang and a slope, leave the flue tile room to move, and only then treat the masonry below with a breathable water repellent that lets trapped moisture escape while blocking new water from entering. A film-forming sealer does the opposite and makes spalling worse.
Repointing versus rebuilding
Where joints are eroded but brick faces are intact, cutting out old mortar and repointing buys decades. Where the faces have popped off and the units have gone soft, repointing is money spent on something that will fail again, and the top section needs taking down and rebuilding. We show you the photographs behind whichever recommendation we make, and we do not sell a rebuild to a chimney that only wants pointing.
Questions
Chimney Repair in Sandy — common questions
There are flakes of brick face on the roof below our chimney. What is that?
That is spalling, and it means water has been getting into the brick and freezing. The outer face comes off first. It is worth acting on early, because once enough face is gone the unit itself softens and pointing will no longer hold it together.
Can you do masonry work in a Sandy winter?
Small emergency work and temporary weather protection, yes. Real mortar work, no. Mortar has to cure above freezing or it never reaches full strength, and a crown poured in January tends to crack the same year. We would rather protect the chimney through the cold and do the repair properly in spring.
Should we just seal the whole chimney to keep water out?
Only with a vapor-permeable repellent, and only once the crown and flashing are sound. Masonry has to be able to dry outward. A glossy film sealer traps moisture inside the brick, and the next hard freeze does more damage than leaving it alone would have.
Water shows up at the ceiling near the chimney, not in the firebox. Is that the masonry?
Very often it is the flashing instead. Where the chimney passes through the roof there are layers of metal that have to be woven into the shingles, and they are a frequent failure point. We look at flashing, crown and brick together, because guessing between the three wastes your money.
Also in Sandy
Our other services here
Chimney Sweep Inspection Fireplace Repair Installation Gas Fireplace Caps & Dampers Dryer Vents All Sandy services
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