pouring cement in winter

[jmc]

Its time for putting in a cement floor in the new pole barn. Next week the temperatures should range from the mid 40's to the mid 20's at night. Is this too cold for good concrete without some kind of additives? Do the additives weaken the cement significantly? Yes, I should ask the contractor but he wants to keep busy and also, probably does not have a 20 yr perspective. It could wait until spring since its got a compacted gravel base but it would be nice to have it done.

Thanks.

John

 

[kn6md]

I believe some accelerators attack steel, but your contractor would know about that. I had a garage slab poured in early November of last year (Carson City area of Nevada) and the contractor ordered hot water in the mix to get things going. I let it cure for a month before I drove on it. My guess is that if your contractor came highly recommended, you and your slab will be just fine.

Regards,

Bill Vorhies

 

[JASTN70D]

The good side is that the slower it cures the stronger it is. the bad side is that if it freezes before most of the water is out it could present a problem. I have seen where it is covered with straw at night if they don't use an accelerator of some type. It seems everyone does it different. And time to finish is the driving force about how it gets done. If your just getting a bull float/brush finish I would not use an accelerator

 

[Junkman]

I have been told that they put calcium chloride into the cement to keep it from freezing. I don't advise pouring a floor in freezing temperatures and would avoid it at all cost. One of the problems is that the floor always leaches out the salts and this is corrosive to anything that it comes into contact with, such as steel. If you can have it poured without the calcium, and cover it with plastic and hay, it will not freeze unless the temperatures drop drastically. When I worked on a home construction site one year in college, the contractor would never pour in the winter and they always got all the foundations in during the fall. Many times, the foundations would just sit until the framing crew got to them.. The contractor isn't going to live there, so they don't have the same concerns as you would as the homeowner...

 

[DUMBDOG]

They poured the cement in my pole barn in November, sealed up all of the vents and used heaters for a few days to let it cure properly. After three years the only cracks that I have are at the end of the expansion cuts.

 

[Wildman1]

I had the option of pouring in November in Alaska on a new addition. After checking this out 2 problems were found: chances of a substandard floor and significantly higher costs due to additives and heat. So....I waited until spring.

 

[rtimgray]

This is going to seem really picky, but the terms "cement" and "concrete" are not interchangeable. Cement is a component of concrete, not the final mixture. If you actually poured cement, you would have a big, cracky mess.

Sorry jmc, it's not just you that does that - tons of folks do and I know what they mean but it bothers me. My boss at work once told me "you know, we should pour a cement curb around that mixer to keep the water from spilling" and I said "you mean concrete, right" and he said "ah...same difference". So I really wanted to pour a cement curb...but then I decided I wanted to keep my job.

If your low temperature for 4 or 5 days is going to be 20 degrees, and you really want the floor poured, I'd say just add hot water and cover it when you're done (concrete generates heat as it cures). If you can stand to wait until spring, then go ahead and wait and you know you can't go wrong.

Again, sorry about the cement:concrete thing; just struck a nerve.

 

[have_blue]

You will need about 4 days with temps no lower than mid 20's. Concrete generates its own heat while curing, that's why it takes colder temps to freeze it. Plastic film would be good insurance if temps threaten to go into the mid 20's before the 4 day period is up. Slow curing in cold weather make it stronger than normal.

 

[TimSullivan]

Thanks for the post. We are trying to decide whether to start a home in New York State. The weather here can vary in the winter and we were hoping for some warmer temperatures. The nights have been in the teens or low twenties and I just don't want to pour in that range.

Looks like we will be waiting until spring which was the original plan anyway.

 

[5030]

I'd wait until late spring, when the temperature is stabilized.

You can use calcium chloride as an accelerator but anything that's in contact with the floor when you begin to use it that is of a ferrous nature will corrode due to the leaching effect of the calcium chloride.

As you already have your gravel base, just put some more skirt boards on the uprights to keep the snow out and pour in the spring.

It would be much easier on you and the floor will probably last longer.