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Talking to a mason in Cincinnati made me question my mortar mix for a cold snap job
He said he always adds a cup of calcium chloride to his mix when the forecast dips below 40, which I've always avoided for fear of efflorescence. I've got a small patio job lined up for next week and the low is supposed to be 38. Is that old-school advice, or is he onto something?
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mark_fisher481mo ago
Why risk it for a low that close?
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ray21011d ago
Been there last fall with a low of 36. I skipped the calcium and just mixed with hot water from a thermos. Kept the bricks next to a space heater in the garage before laying them and covered the whole patio with a tarp and an old moving blanket for two nights. It set up fine with no white haze. That extra cup seems like overkill for such a mild chill.
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jake_mason301mo ago
That guy's advice is straight out of the 80s. A cup per batch is a crazy amount and will absolutely cause problems later. For a low of 38, you're barely freezing. Just use warm water, keep the mix covered, and maybe throw a tarp over it at night. It's a patio, not a skyscraper.
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