We're in the same situation (Illinois). I've had several contractors tell me the foundation must be poured by Christmas at the latest. It is possible to have it done in January/February, but it's not desirable.

We live in Northern Illinois and we broke ground on our house the third week in January of 2010. It doesn't appear to have presented any problems.

Sidney4, did they use the special additives in the concrete for winter curing? Or set up heaters for a week? Or ... was the weather just unseasonably warm that week in January?

We started building just before Thanksgiving last year in Cincinnati. In our area they can usually pour till Christmas. Last year they could not pour starting at Thanksgiving. Our foundation plates sat in the ground till the last week in December when they had four days that they could use. With all the additives and warm water they can pour as long as it stays above freezing for 48 hours after pouring.

I wondered if there might not be windows of warmer weather that would open up so we could get started. Last winter was brutal everywhere - you were lucky to get four days in December! My builder did say that last year they didn't pour after Thanksgiving, but many years they could pour in December. I haven't checked the weather predictions for this winter, but if it's like last winter, we're probably facing delays with our timing I guess.

Mjtx2, Our builder waited for a break in the weather with several days of decent weather thereafter. We had hoped to break ground after Christmas but had to wait it out until mid January. It was an unnerving process for me because we needed to move that summer......fortunately the weather cooperated.

We're in Wisconsin with the same situation. Our builder has told us that they can add stuff to the concrete to make it harden faster if needed, since we want to get a foundation poured in early November. (By Nov. we have freezing temps at night and above 32 degrees during the day, typically.) We may not need the additives The additives make the concrete more expensive, he warned us, but not overmuch. He also said, if it gets too late, another option is to pour the foundation walls now, build the structure above, and then enclose the house. The basement floor would be poured when the weather got warmer.

He said the important thing is that the septic mound system gets dug and fitted before it gets too cold.

It really depends on where you are building and the winter weather patterns. The first night of the pour the concrete should be ok even if it is freezing since it is 'hot' they will add special chemicals to help it but the 2nd and 3rd nights really are crucial. My husband is a commercial contractor so from listening to him so much I really have learned a lot about concrete! Sometimes they will tarp it or use heaters which can become really costly. I would say the best person to ask is a local concrete plant as many times they even offer classes to contractors to teach them about the different additives and things like that to help in those situations.