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Discussion Starter · #1 ·
Looking for a little insight from more experienced fellers than myself. Due to a number of different reasons, we need to pour footings on a new 10,000 sq ft home if not this week, then next. We're in the Kansas City area, so it's not exactly the weather I prefer for concrete. We dug the footings a couple weeks ago, there was 6" of frost. Right after we dug, we covered everything really well with concrete blankets, then got a little snow on them. Then we got some below zero temps. I haven't checked just yet to see, but will the blankets keep frost out of the ground? We haven't formed anything yet, so the blankets are tight against the ground, well beyond where we dug. We've got some more cold weather this week and we need to get formed. Our footing will be 16" deep and 36" wide, so we'll form one section at a time and cover it again, but will we need to blow heat in there to keep the ground warm before we pour? I've always managed to keep all my concrete work in decent weather, so this cold weather stuff is a little new to me, and there's no way I'm willing to compromise this. It will be done right or not at all. Some more experienced insight will be appreciated. Thanks in advance.
 

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Discussion Starter · #3 ·
Yeah, I'm familiar with the hydronic ground heaters, and other ways to thaw the ground out. I checked this morning and under our concrete blankets we don't have any frost in the ground, so they're doing their job. It was around 10 degrees this morning. But once we get our forms built and place our blankets over the forms, there will be an air space of about 36" x 16". Will the blankets still keep the frost out of the ground until we pour, or should we stick some heat under there? And once we do pour, will the concrete generate enough heat that once it's covered, even if the temp drops down in the single digits over night, will it be okay? I just haven't done enough cold weather pours to know the limits here.
 

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Did I read that right? 36" wide footings that are 16" deep?!? Wow.

We have used hay with plenty of success.......once it's excavated, obviously it's best if you can form immediately......fluff up hay over the footing area, and a couple feet in each direction.....IF it's gonna freeze...

Pour footings when temp allows, and repeat with fresh hay.

I've got curing blankets and some heating blankets, but the hay has worked the best....it's a great insulator.....

In a perfect world, the hole would get excavated before a stretch of good weather, but I find that they usually dig right before a cold spell.....:laughing:

You could always form a temporary tent with PVC and reinforced poly, making sort of a low quonset hut......we've done that as well, but with a 10,000 sf home, that might be a major task.......Good Luck!
 

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I can add from past experience doing concrete and masonry in cold climates both residential and commercial. Good quality frost blankets will definitely benefit you.
You have already seen the effect of good blankets, in that you mentioned that you had 6" of frost before you placed the blankets. You then checked under the blankets and frost was not apparent, as the temperature of the ground underneath was enough to thaw what little frost was there.
With regards to needing additional heat after you pour your footings; In your climate I do not believe that any additional heat will be needed. We all know that fresh concrete generates heat due to the catalyst of adding water to Portland cement. So with the correct mix design i.e. warm or hot water to have concrete delivered to site with mud temperature at 60 degrees and then (if allowed in your specs) using a NCA, place concrete in a timely manner, then cover with blankets.
Now if you have re-bar dowels sticking up out of footings, we would lay blankets on each side of dowels to assure of blankets being tight to footing concrete.
 
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