It’s snowing out today, and I’m holed up inside with a nice hot mocha planning out my current project to work around the weather, so I figured today would be a good day to talk about what it’s like doing masonry in the winter.
It’s not bad in Colorado, where the winters are relatively mild, especially compared to Minnesota where I grew up, but there is definitely some considerations to make.
The most important thing is to not let mortar freeze within 24 hours of laying it. You can keep mortar from freezing by covering it with tarps, and there are special insulated tarps if it’s going to get especially cold.
Normally if it’s going to be just above freezing at night, I stop a little earlier in the day to give the mortar time to set up before it gets cold. The colder it is the slower mortar cures, which is an advantage because slow curing makes it stronger. However, freezing the water in the mortar will damage it.
Another important thing is to use warm water and warm sand when mixing mortar. I recycle the water used in cleaning my tools to mix mortar the next day and leave it in buckets overnight, but when it freezes overnight the icy water has to be dumped out and you have to use fresh water. You also have to spread the sand used for mixing mortar out in the sun if it freezes, because water in the sand will freeze it into icy sand chunks. You don’t want ice sand chunks in your mortar while you’re trying to lay stone!
In situations like today, when it’s going to warm up again right away, I will just take the day off and go back at it again when it’s nice out. If it’s not going to be nice for a while, there’s things like site prep, material staging, digging, or hauling gravel you can do to stay productive and get ready to lay when it warms up again.
If you absolutely have to do mortar or cement work when it’s freezing, you will have to use warm water for mixing, keep the stone and sand sheltered out of the cold, and set up a heated tent from tarps or plastic sheeting over the work area. I’ve worked like this before, and I’m definitely thankful for the mild winters in Colorado.