HI all.. My project is taking longer to get started than I thought. Is there any limit as to how cold it can be to pour successfully? I'm in the upper midwest... Thanks, -m

This is usually determined by concrete manufacturers. In NH & VT, about 20 degrees F is their limit. The other consideration is, that even if you can get concrete delivered, a concrete pumper may be unwilling to work. His boom will be extended high in the air, and despite the fact that concrete creates heat, those steel booms can get very cold and they don't want concrete clogging up in cold weather. There are many other considerations, such as putting heat blankets over the top of the wall after concrete placement.
b merritt

We have poured down to the single digit temps, but not again. I would say 15 degrees and no wind or over 20. And Ask you ready mix at what temperature you will get the concrete, and use a thermometer.

We had a job 14 degrees and windy. Ready-mix plant 2 miles away. Unbeknownst to me they closed the plant and brought the concrete from another plant, the third driver got lost and was late. The pump operator kept recirculating his 1 yard, further cooling it, but keeping it from freezing in the boom. The concrete from the third truck froze on the top of the wall, before we could screed it. It was bad, a $10,000 fix.

Hot water is automatic here, Minnesota, extra cost of course.

We also get hot water added to the mix around the end of October also for extra cost.

So I guess I shouldn't worry about starting my project in November? I could wait until spring if it's less risky. I also worry about things like roofing shingles installed in winter (they won't seal properly until hot weather, right?) or me being outside in December installing the siding. I suppose that could wait 'til spring to install?

Thanks,
-m

Check also with your local building official. Some jurisdictions have restrictions on how cold it can be and still allow you to pour. There are other options like heaters, blankets, tents, etc., but those all cost money, money that will not add to the final project value. The footer and flat work are the real problems as those are susceptible to freezing. The concrete inside the ICF forms should be OK unless it's really, really, cold. Like others have said, it will be pump boom and the top bit of concrete in the wall that is susceptible to freezing.

Roofing in cold weather can be a problem if you are in a dry dusty area. The builder who worked with me said that around here, SW Idaho, you could tell when a roof shingles had been put down in cold weather. Before the weather warmed up enough to set the seal dust had blown in between the shingles. The dust kept the shingles from sealing properly.

If you wait until early spring to start you can look forward to the days getting steadily warmer. That's a lot more comforting than realizing every day will be colder than the previous day for several months running if you start in late fall.

I agree the ICF walls are not much of an issue. Not only do you not want the footings to freeze for at least a week, you want to make sure frost does not get under the footings, ever.

ACI 306 (Cold weather Concreting) covers all the info you need on the topic. There really are a lot of options.

Why not then consider building with SIPs? We have done some ICF's but it's a lot of work in cold temps (and costs). We have easily built commercial buildings in the middle of winter, at -40C with wind and no problems. When the building is tight, we heat it and leave it for a week and the heat defrosts the ground inside and we can then pour the floor. Besides concete is too expensive and of course unmanageable at those temperatures. But when we pour our floors, we can mix inside ourselves and presto, all done!

Thanks for the input. I've heard that SIPS are a good idea...IF you can find a crew who knows how to build with them. I have confidence in my ICF builder. There just aren't many SIP guys around here. I also like the sound deadening and mass etc of the ICF walls....

-m

If you have the choice it seems that waiting until the spring would make a lot of sense.

Not sure what to do.. I don't want to lose my financing. As I understand it, the biggest problem is pouring the garage slab because it's on grade, unprotected, more or less. I suppose I could wait til spring to have it poured? But then a lot of dirt/dust would get tracked into the house...

Thanks,
-m

Gonna happen anyway!! From my one time experience it's nigh impossible to keep dirt and dust out during construction. Regular cleaning up will be a good part time job for some local money hungry dependable teen. Wage will be less than what your time is worth doing actual construction.

Just work quick and protect the ground and the concrete from the cold. I wouldn't hesitate to start during the winter. I have started houses in January and February and it can get cold here, you just have to be prepared.

Besides, said teen's mother will worship you.