Pouring Foundation in Winter?
does anyone have any experience with pouring a concrete foundation (for a brownstone extension) in winter (around early january)? is this absolutely a bad idea, or is it ok? thanks!
does anyone have any experience with pouring a concrete foundation (for a brownstone extension) in winter (around early january)? is this absolutely a bad idea, or is it ok?
thanks!
If you have a good contractor there is absolutely nothing to worry about. If the outdoor temp is close to freezing the concrete supplier should add an accelerant usually <2% calcium chloride and maybe insulation for the forms. As it sets the concrete generates significant heat. It only needs protection until it has set, usually 24hrs is plenty depending on the mix and the accelerant.
i poured a foundation wall at my home in NW CT in March [ read: real cold ]. The foundation contractor wrapped the forms in big plastic blankets.
The wall is just fine. I believe as concrete sets, it is exothermic, meaning it gives off heat.
After fixing a cement staircase 8x’s during the winter around January for a commercial building (it would make sense after the 4th to stop but if it’s the only way to walk into the building, what are you going to do) you realize, you don’t mess with mother nature. Different cement was used as well as hydraulic (I may have mispelled that) cement, it all ended in crumbles. We didn’t do a tent though we did cover it with tarp and blanket to achieve a similar effect. I like sundial’s answer b/c it’s the more correct answer but from one who went through it, personal opinion, too many factors come to play, just wait if you can. The frustration of it not working out and having to fix it is not worthwhile. It’ll cost you more to repair and redo. Now, rather than patch that stair in the summer, we are redoing the whole thing to avoid any issues the following winter. Everyone agreed this was best.
i recall adding a special agent to the concrete—a powder—that keeps it from freezing. that way, we didn’t have to tent the slab while it cured. I did cover it w/ tarps, though.
You will need to tent and heat the slab while it is curing to keep the area above, I believe, 40 degrees Fahrenheit. Your Structural Engineer should be able to weigh in on this.
And you can also research the Portland Cement website, if technical concrete facts float your boat:
http://www.cement.org/index.asp
Hope this helps.