I am in the process of getting at lot ready for house construction. I will have time to pour the foundation before winter, but not to close in the house. The house will have a basement. Technically, I am concerned that the footings could potentially heave with the frost even if I back fill. Do I need to wait for the foundation pour until next spring or am I worried about nothing?
This is my first post – so hopefully I have done things right
Thanks for any thoughts
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Replies
As in real estate location means everything.
If you're in our northern climate you will have to protect the inside of the foundation footings if you can't heat the foundation.
Backfilling will protect the outside of the foundation but leaves the inside exposed to frost damage. You can put down a layer of straw around the perimeter and that will do a fair job of protecting against heaving.
Gabe
As Gabe said, I live in Montreal Canada, And quite often see straw put around concrete to keep it from freezing.
If you are using a concrete sub you might be able to talk him into leaving you some concrete blankets, too. Most guys who do a lot of concrete seem to end up with a pile of old blankets that have been around 2 or 3 years, they're pretty bad, but not bad enough to throw away.
You can ususally get those on loan for a few months. If you do like Gabe said, put some straw down on the ground while it's still warm, and cover that straw with blankets, it will help.
To get a frost heave you need three things: moisture, cold, and suitable soil. ("Suitable" is probably the wrong word, but you get the point.)
Remove any one component and you won't get a heave. The temp hit 9 degrees Farenheit here less than a week after we poured a slab and never went above freezing for about 2 months before we got the heat turned on and we had no problem. The soil moisture content below the slab was about 12%, and there was more than enough clay to make a problem. A layer of 6 mil plastic and two layers of blankets did the trick.
DRC
Keeping the moisture out of the soil by using soils that drain does the trick for me.
The other concern here is that if you backfill green concrete without a deck built to the bolted sill, the walls can heave inward. They would need to be backbraced.
Excellence is its own reward!
I second Piffin's suggestion. If you can brace the foundation, you will need to put hay around the outside of the foundation as well. I suggest that you frame and sheath your deck and lay rubber roofing over the sheathing, seaming the joints but not glueing the roofing. Probably the most cost effective plan is to simply wait, unless you are doing all the work yourself.