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Got a call back for a chimney rebuild I did in 2018 because the crown cracked.
I used to build crowns with a basic 1:3 cement mix, but after that one failed in under five years, I switched to a pre-bagged, high-flex mortar with polymer additives. The freeze-thaw cycles here in Michigan just wrecked the old method. What's your go-to mix for a durable crown that can handle serious weather?
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thea1436mo ago
Is a special mix even the main problem here? That 2018 crown lasted a while, so maybe the crack is just from normal settling. I've seen plenty of chimneys where the bricks underneath shift a tiny bit and crack anything on top, even the fancy mortar. Could be you just got unlucky with that one spot.
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caseyl186mo ago
Ever think about what's happening under the crown, like the chimney's footing? If water's getting in and freezing below it, even a perfect crown mix can fail from the ground up. A good crown is key, but it's the last line of defense. Make sure the whole chimney structure, especially the very top bricks it sits on, is solid and sloped to shed water away first.
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