Grant Park crown repair: the difference between a crown coat and a new crown
Two Grant Park chimneys, same street, same week. One got a sealant coat, the other got formed and poured. Here is how we decided.
The first chimney
A 1960s ranch on the north side, the part of Grant Park rebuilt after the 1954 tornado. The crown was original: a proper concrete slab, about two inches thick, with a small overhang. It had a network of hairline cracks and one crack about an eighth of an inch wide running from the flue tile to the edge. No pieces missing, no sag, the slab still bonded to the brick. That is a crown coat job. We cleaned it, filled the wider crack with a flexible sealant, bridged the joint around the flue tile so the tile can expand, and applied two coats of elastomeric crown coating. It stays flexible through freeze-thaw and should protect the slab for a decade.
The second chimney
Three houses down, an older home with a crown that was never a crown. It was a thin wash of mortar smeared over the top course, maybe half an inch thick at the edges, bonded hard to the flue tile. It had cracked into pieces, several of which were missing, and water had been running into the top courses long enough that two bricks were loose. Coating that does nothing; there is no slab to protect. We removed the wash and the two loose bricks, reset the bricks, built a form, and poured a new crown two inches thick with a one-inch overhang, a drip groove underneath and a bond-break around the tile. It cured two days before the cap went back on.
How to tell which you have
Thickness, overhang and whether pieces are missing. A real slab with cracks gets coated. A mortar wash, a sunken crown, or one with the edge broken off gets rebuilt. On a chimney in open country like Grant Park, where the crown takes the full weather, doing the right one is the difference between a repair that lasts and one you repeat in three years. We look at every crown from the roof during a sweep and tell you which you have.
If this sounds like your house: we handle crown repair and chimney caps across Kankakee County, and our Grant Park page covers what we usually find there. Call (815) 449-4264, 7am to 9pm, any day.
Quick questions
How long does a crown coat last?
About ten years on a sound slab, longer if the chimney is capped and the brick is in good shape.
Can I coat a crown myself?
Crown coating products exist for homeowners, but the job is on the roof and the prep matters more than the product. We do not recommend it.
How thick should a crown be?
At least two inches at the thinnest point, with an overhang and a drip edge.
Does the cap come off for crown work?
Yes, and it goes back on after the crown cures, usually two days for a poured crown.
Published September 29, 2026 · Updated September 26, 2026 · By Jacob Dove, Friendship Chimney Sweep, Bourbonnais IL