# Concrete Foundation in Winter... Very worried!!!



## ChathamJedi (Jan 9, 2010)

I live in Southwestern Ontario Canada. My house foundation (walls and footings) were poured in late November. It is currently 1 week into January and there has been no sub floor yet, nor have they poured the basement floor. Another contractor mentioned to me that I should be concerned due to the cold... should I be, and how can I tell if there may be a future problem.. what are the signs?

Pouring tempature was aprox 10 degees (C) or 50 degrees (F)
Current Tempature is -15 degrees (C) or 5 degrees (F).

Without a concrete floor in or a sub floor do I have something to worry?


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## jlhaslip (Dec 31, 2009)

Won't be much 'sign' until spring after the ground thaws. Worst thing to watch for is water getting under the footing and jacking the footing up. It likely won't be good if that happens. Check the top of the wall height with a level before the subfloor goes on.


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## Bob Mariani (Dec 1, 2008)

Was the foundation protected from weather? If so, for how long and how? If not...WORRY! and then build over in the spring.


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## jomama45 (Nov 13, 2008)

A few questions:

- Is the foundation backfilled?
- How much snow is in the basement?
- Has anything like hay or insulating blankets been laid out in the basement?

BTW, a concrete floor will offer little to no frost protection in your situation.


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## ChathamJedi (Jan 9, 2010)

jomama45 said:


> A few questions:
> 
> - Is the foundation backfilled?
> - How much snow is in the basement?
> ...


Yes the foundation was backfilled right away (november 25th)
Very little snow (1-3 inches overall)
There is hay over the footings


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## ChathamJedi (Jan 9, 2010)

jlhaslip said:


> Won't be much 'sign' until spring after the ground thaws. Worst thing to watch for is water getting under the footing and jacking the footing up. It likely won't be good if that happens. Check the top of the wall height with a level before the subfloor goes on.


Yes this is what I am also worried about... jacking the footings up. does a subfloor really provide that much heat difference?


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## jomama45 (Nov 13, 2008)

ChathamJedi said:


> Yes the foundation was backfilled right away (november 25th)
> Very little snow (1-3 inches overall)
> There is hay over the footings


I would personally make sure there was 2'+ of hay over all footings, including post pads & any bearing wall footings.



ChathamJedi said:


> Yes this is what I am also worried about... jacking the footings up. *does a subfloor really provide that much heat difference?*


 
No, it can protect a little, as well as hamper the basement warming up when the sun comes out.


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## Gary in WA (Mar 11, 2009)

Hopefully you have a working drainage system outside at the footing level to remove the water in the back-fill that could otherwise freeze, forming ice lenses and jacking the walls/footings, as required down here- IRC 405.1 http://www.servicemagic.com/article.show.Foundation-Drainage.13702.html
http://www.waltersforensic.com/articles/civil_engineering/vol1-no11.htm

 Also, down here our code makes us install the first floor system to keep the over 4’ high concrete walls stable before back-fill compacting exerts forces on them, or if subject to hydrostatic pressure required in their design—IRC 404.1.3
Do not install back-fill above 4ft. until walls anchored to the floor- IRC 401.7


Just sight along the top of the walls for level and straight (bowing in) from the top corners.


Be safe, Gary


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## Daniel Holzman (Mar 10, 2009)

If your concrete was properly placed and cured, and was placed on gravel rather than frost prone silty soil, the lack of a subfloor will have no impact on the concrete. But GBR is absolutely correct, it is typically a bad idea to backfill a concrete wall without the floor joists in place, since the concrete is prone to deflection and cracking. Based on your post, it sounds like the wall was backfilled, so you should check it for deflection and cracking, especially come spring when the water table is likely to be high, and the soil pressure at a maximum.


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## jomama45 (Nov 13, 2008)

GBR in WA said:


> Also, down here our code makes us install the first floor system to keep the over 4’ high concrete walls stable before back-fill compacting exerts forces on them, or if subject to hydrostatic pressure required in their design—IRC 404.1.3
> Do not install back-fill above 4ft. until walls anchored to the floor- IRC 401.7


Gary, aren't you allowed to brace the foundation walls in lieu of capping the basement? "Footlock" bracing is the norm around here, although most contractors generally don't use enough braces IMO. It's still very, very rare to see any issues backfilling a basement around here before capping due to current foundation standards we have.


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## Scuba_Dave (Jan 16, 2009)

Daniel Holzman said:


> If your concrete was properly placed and cured, and was placed on gravel rather than frost prone silty soil, the lack of a subfloor will have no impact on the concrete. But GBR is absolutely correct, it is typically a bad idea to backfill a concrete wall without the floor joists in place, since the concrete is prone to deflection and cracking. Based on your post, it sounds like the wall was backfilled, so you should check it for deflection and cracking, especially come spring when the water table is likely to be high, and the soil pressure at a maximum.


I'm curious as to this since in a lot of cases the garage floor is left until last ?
Garage is normally open to all weather all the time
The floor isn't poured until near the end so it will be in "pristine" condition for the new owner

Ah - basement VS garage - different
My walls are backfilled on both sides evenly


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## Gary in WA (Mar 11, 2009)

jomama45 said:


> Gary, aren't you allowed to brace the foundation walls in lieu of capping the basement? "Footlock" bracing is the norm around here, although most contractors generally don't use enough braces IMO. It's still very, very rare to see any issues backfilling a basement around here before capping due to current foundation standards we have.



"IRC code section R404.1.7 states that “backfill shall not be placed against the wall until the wall has sufficient strength and has been anchored to the floor above, or has been sufficiently braced to prevent damage by the backfill”. This includes pouring the basement slab within the basement wall.
Exception: “Such bracing is not required for walls supporting less than 4’ of unbalenced backfill”." ------ From: http://www.co.henrico.va.us/dyn/med...00/000000/00000/0000/000/22/BasementWalls.pdf
Tricky wording, that. 

A lot of pressure to restrain, depending on the soil type: http://www.servicemagic.com/article.show.Designing-Concrete-Basement-Walls.13696.html

If the perimeter drain is not working, the back-fill soil will be saturated with water, able to create ice lenses to heave the walls/footings: http://www.phbia.com/pdf/PHBIA ANHWP Rev 5 March 2009.ppt

Be safe, Gary


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## Michael Thomas (Jan 27, 2008)

Concrete does not achieve full strength for 25-30 days - longer in cold weather. A standard recommendation is to wait 5-7 days before backfill, 10 days in cold weather. Many contractors don't wait, but that's what the books recommend, see for example see pages 23-24 at http://tinyurl.com/yffzx4h


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