Repairing Kearns Chimneys and Chases

Thin crowns and what they cost later

The crown is the concrete slab across the top of a masonry chimney, and its job is to shed water away from the brick and the flue tile. Built properly it is a few inches thick, sloped, and it overhangs the brick with a drip edge. Built quickly, which describes a lot of construction from the boom years, it is a thin skim of mortar troweled flat across the top with no overhang. That version cracks within a decade, and once it does every storm feeds water into the top of the stack. Almost every serious masonry problem we repair in Kearns started as a failed crown that nobody could see from the ground.

Freeze-thaw on the valley floor

Cold nights, sunny days, and repeated cycles across the freezing point while the brick is still wet. Saturated masonry that freezes pushes its own face off in flakes. It shows first on whichever elevation dries slowest, and once the fired surface of a brick is gone the soft interior soaks up more water than before, so the process speeds up rather than settling down.

Wind from the west is a real load

The west side of the valley catches weather coming across open ground from the Oquirrhs and the desert beyond, without the shelter of a foothill or a mature tree canopy. Wind-driven rain does not fall on masonry, it is pushed into it, and a driving storm wets the windward face of a chimney far more thoroughly than a still rainfall ever would.

Framed chases have their own problem

Many homes here have a sided chase rather than brick, with a metal chase top at the top of it. Those tops are typically galvanized, they rust from the middle outward, and when one perforates the water goes straight down the inside of the chase into framing you cannot see. Replacing a rusted top with a stainless one built with a cross-break and a proper collar is cheap next to the framing repair that follows leaving it.

What we will and will not do

We repoint where the brick is sound, rebuild above the roofline where it is not, and replace crowns rather than smearing sealant over a broken one. If the honest answer is that the stack has gone too far to patch, we say so, because a repair that fails in two winters is not cheaper than doing it once.