Talking to a concrete guy made me switch up my mortar mix for cold weather

I was working on a garage foundation in Grand Rapids last month, and the temp kept dropping below 40. My usual mortar was setting way too slow. I was complaining to the concrete guy on site, Pete, and he just shrugged and said, 'You know they make a type N with an accelerator in it, right? It's not cheating.' I always thought using anything but the basic mix was cutting corners. But he explained that on a commercial pour, they always use an accelerator when it's cold to control the set time and avoid freeze damage. So I grabbed a bag of that pre-mixed type N with accelerator for the last few courses. The difference was huge. It set up nice and even, and I didn't have to worry about the overnight frost. Have any of you guys used the cold-weather mixes, or do you stick with the standard stuff and just work faster?

3 comments

3 Comments

tyler61mo ago

Wait, you were working with mortar below 40 degrees without an accelerator? That's asking for trouble. I'm surprised the whole foundation didn't turn to mush. Pete was right, it's not cheating at all. Using the right mix for the weather is just doing the job correctly.

olivia_harris191mo ago

Seriously, how did that even hold together overnight? Tyler6 is totally right, it's just asking for a disaster. I saw a crew try that on a patio job last winter and they had to chip it all out the next week, it was a complete mess. Using an accelerator in the cold isn't cheating, it's the only way to make sure the stuff actually sets. Some guys just want to skip a step and then blame the mix later.

margaret3041mo ago

We used a non-chloride accelerator on a cold pour last month and it set up fine. The key is mixing it in right and not adding too much water. Skipping it just wastes time and material when it fails.