Home › Crown repair
Chimney crown repair and replacement
The crown is the sloped concrete cap that sheds water off the top of the stack. In this climate the crown is the part most likely to fail first, and the failure that causes the most downstream damage, because every crack feeds water directly into the heart of the masonry below.
Why crowns fail here
Most mid-century crowns were poured thin from regular mortar rather than proper crown concrete, with no overhang and no expansion gap around the flue tile. Sixty winters of saturation and the occasional freeze produce hairline cracks, then open cracks, then chunks. A failed crown is the reason so many chimneys in Fircrest and University Place show spalling in the top six courses of brick: the water came in from the top.
Repair versus replacement
Hairline cracking on a structurally sound crown takes a flexible crown sealant rated for our wet-dry cycling, a maintenance-grade fix with real service life when applied to a sound base. Crowns with open cracks, delaminated sections, or improper slope get replaced: the old crown comes off, a new one gets formed and poured with proper overhang, drip edge, slope, and a bond break around the flue so seasonal movement stops cracking the pour.
Common questions
How do I check my crown from the ground?
Binoculars from the driveway. Look for visible cracks, staining running down from the top of the stack, or vegetation growing at the very top. White staining just under the crown almost always means crown failure.
How long does a new crown last?
A properly formed crown poured with the right mix, overhang, and bond break should outlast the rest of the chimney. The short-lived crowns are the thin mortar washes done as an afterthought.
Can crown work be done in winter?
Sealant work needs a dry window and moderate temperatures, which this climate provides even mid-winter. Full pours are best scheduled in the drier half of the year. Fall booking fills first.