Question about mixing mortar for a cold weather job

I had a chimney rebuild in December where the temp dropped to 25 degrees. The old way, I'd just chuck in some extra calcium chloride and hope for the best, which led to some weak spots and efflorescence later. This time, after talking to a supplier in Boise, I switched to a pre-blended, non-chloride accelerator. The big change was heating the sand and water first in a drum with a propane heater for about an hour before mixing. The mortar stayed workable, and the set was way more even. It added maybe 90 minutes to the prep, but the bond is solid with no white stains so far. Has anyone else tried a full heat-and-accelerator combo on a small residential job like this?

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3 Comments

iris_jones895mo ago

Heating the sand and water" is exactly right, I've done it on a few porch steps and a small wall job and it makes a huge difference with cold weather work. Just watch you don't scorch the sand or you'll mess up the mix ratio.

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cameronwood6mo ago

Heating the sand and water? For real? That's some next level prep right there.

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hugo_hayes6mo ago

Remember when people used to heat up rocks to boil water in a hole? I tried that once on a camping trip. Took forever to find the right stones that wouldn't explode.

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