Ideally, home building is a year-round job, but in many places, winter can throw a wrench into the works. In this Q&A post, “Emel” is worried about his upcoming foundation pour. He’s in central Wisconsin (Climate Zone 6), and the pour is scheduled for mid-December, when the daytime temperatures in his area average a high of 27°F.

He writes that the 5-ft. stem walls and footings may be exposed to freezing temperatures for a period of time until the forms are stripped, exterior insulation is installed, and the soil is backfilled. Although the contractor plans to use additives that can allow the concrete to cure in colder weather, Emel is concerned that freezing temperatures may cause frost-heave and affect the stability of the foundation. (For a Canadian take on cold-weather concrete, read this). Emel is also concerned that the cold may affect adhesives, tapes, and caulk in the later build stages.

Fresh concrete needs a little heat

Reader Bill Wichers suggests protecting the concrete with polyiso foam. “The concrete and the natural heat from the ground, plus the heat from the curing concrete will be enough to keep things safe,” he says.

“Weather conditions play a big part in this,” Bill adds. “If 27°F is your daily high, it’s probably safe to assume the daily low is a fair bit below that, so you’re probably in the ‘too cold’ [to pour] territory unless you add a heater ($$). In my area, we tent when it will get down to freezing or a little below, maybe down to 25°F or so as the daily low, if that. It’s similar to the difference between a frost, where tenting your garden can save the plants, and a hard freeze, where the plants are going to die regardless of what you do…