Pouring Concrete in Cold Weather

[Sticks&Strings]

I poured my flatwork on my last house in the 50's. It took 2 days to get it where I was comfortable walking on it and didn't drive on it for 6 days. Don't rush your build...especially with the concrete. If you pour it saturday, give it a week before putting any weight on it. I would rather pour in the 50's than in the 90's, but you just need more time. In the 90's, I am framing in 3 days. And watering the slab while it's drying to prevent cracks.

Tell your GC or whoever is in charge that you are ok with it if he is, and if it has issues he is liable. Make him sign something. You will know then if it's ok.

[klooney]

We pour when it's cold out quite a bit, 2% calcium and hot water from the plant and cover it up after it's finished for a few days and you should be good

[tsu1998]

40 degrees and rising is what most engineers require.

^ This ^.....I know when I do work for the Corp of Engineers they require 50 degrees and rising for 7 days. If it falls below that they make you take it out. Main thing is once it's poured if there is a chance of freezing temps get it covered and give it time to cure.

[wellingtontx]

Dont do it. Cancel it now.

[Tmag]

I poured my flatwork on my last house in the 50's. It took 2 days to get it where I was comfortable walking on it and didn't drive on it for 6 days. Don't rush your build...especially with the concrete. If you pour it saturday, give it a week before putting any weight on it. I would rather pour in the 50's than in the 90's, but you just need more time. In the 90's, I am framing in 3 days. And watering the slab while it's drying to prevent cracks.

Tell your GC or whoever is in charge that you are ok with it if he is, and if it has issues he is liable. Make him sign something. You will know then if it's ok.

This ^^^^^^^^^^^^. Your house, your payment, your problem down the road. Don't take a chance with it. We did not pour until the temp hit 35 or higher because we didn't want to pay for a tear out and repour.

[HandiKap Bowhunter]

I work for the GUBMENT and we will not allow concrete to be poured if it is not atleast 40 and rising like Brent said. Also you have to be concerned about the 3 days after while it is still curing. Those are critical, if it is expected to get below freezing at all those three days you need to make sure they atleast cover it with blankets. The tob layer will possibly crack and sluff and be weak.

[Devin]

You can do it with the temp being 40 and rising as said, and looking at the Hockley weather for the next few days you should be fine with covering the slab.

That being said, if you can wait a few days, it would be safer and should ease your mind. There's just a few more things that need to be done that are critical when the weather is cold. Heck, they have additives and procedures so you can pour through ice, underwater with concrete mixed hours before.... but, you might as well not take the chance if you don't have to.

Here's a typical spec we use for cold weather concrete, fyi:

21. Concreting in cold weather
Methods for concreting in cold weather shall be performed when, for more than 3 consecutive days, the following conditions exist:
• The average daily air temperature at the job site is less than 40 degrees Fahrenheit. (The average daily air temperature is the average of the highest and lowest temperatures occurring during the period from midnight to midnight.)
• The air temperature at the job site is not more than 50 degrees Fahrenheit for more than half of any 24-hour period.

Concrete shall be protected against freezing during the first 24 hours after placement whether or not the average weather conditions specified above for cold weather concreting exist. The following provisions also shall apply unless otherwise specified:
a. When the cement is added to the mix, the temperature of the mixing water shall not exceed 140 degrees Fahrenheit nor shall the temperature of the aggregate exceed 150 F.
b. The temperature of the concrete at the time of placing shall be within the placement temperature range shown below, unless otherwise specified.

Least dimension of section, inches Placement temperature, °F

Less than 12 55 – 75
12 to 36 50 – 70
36 to 72 45 – 65
Greater than 72 40 – 60

c. The minimum temperature of the concrete for the first 72 hours after placement shall not be less than the minimum temperature shown above. Concrete structures shall be immediately protected after concrete placement by covering, housing, insulating, or heating concrete structures sufficiently to maintain the minimum temperature adjacent to the concrete surface. If the minimum temperature requirements are not met and the concrete did not freeze, the protection time will be extended a period equal to twice the number of hours the temperature was below the minimum temperature.
d. Exhaust flue gases from combustion heaters shall be vented to the outside of the enclosure. The heat from heaters and ducts shall be directed in such a manner as to not overheat or dry the concrete in localized areas or to dry the exposed concrete surface.
e. At the end of the protection period, the concrete shall be allowed to cool gradually. The maximum decrease at the concrete surface in a 24-hour period shall not exceed 40 degrees Fahrenheit.

[Wall_Hanger]

Does your GC have the means to steam cure or used heated forms?

[hooked]

42 and rising. With the temps the way they are right now, it will take quite a while to get on it and for it to set up to work it. It just depends on what you are looking for in the finish. If you are looking for a hard trowel finish or something you want to get on in the next few days, WAIT. If it is something that the finish doesn't really matter and you can wait to get on it then go ahead and pour. Remember, the ground will be cooler than the ambient temperature until late saturday or sunday. makes a difference in cure and workability time. If you are paying someone that planned on working it for 6 to 8 hours, they may be likely to charge you more because they have to sit with it longer. You can do things as stated above, but if you got a good price in your concrete, then kiss the good price good bye. Plants will talk you into pouring because they have been shut down since tuesday and they have nothing to lose since your slab will most likely not have an engineers tech take samples for breaks. JMHO, I pour a few yards a year.

[hyperlitejb]

Thanks everyone....I'm just going to wait until it warms back up in a week or so.

[lameduck]

Thanks everyone....I'm just going to wait until it warms back up in a week or so.

Good move