Concrete Slab

[limerockconstruction]

Advice needed please.....I have no real experience of pouring in colder weather (guess i've just been lucky!)

I'm meant to be pouring a slab tomorrow and the temps in my region for the next few days are forecast at 5c. max in the day day and 2c. low overnight. Its a garage slab, so i'm giving it a floated finish.

Any advice welcome.....should I avoid the pour, can I get away with it because its not freezing? Its a pumped mix because its a reasonably large area, so will be reasonably wet, but higher in cement content.

Should I call the whole thing off and chuck in a skirt and pour after the blockwork has gone up?

 

[noseall]

Garage slabs are tricky even in the Summer!

It's not so much how the cold temp's may effect the body of concrete but the amount of time you will have to wait before being able to get a good trowel finish on the surface.

We have had mixed success by leaving the tamped concrete for a few hours then planking and trowelling later on. But you will only get a first rate finish with a power-float.

Whether you will achieve this in the winter is another matter, or whether it may be worth paying for an accelerator to be put into the conc before pouring.

 

[limerockconstruction]

Thanks mate. So the temps wouldn't bother you too much? I wonder how much the accelerator costs?

If I have to go back later to trowel it that's not to much of a worry, I'm just panicked by the cold getting into it. I offered them a power float but they didn't want the extra expense.....

 

[pinenot]

Speak to your pump contractor or your concrete provider, part of their job is to advise!
There are a few options, but if you are really worried and it's going to be pumped anyway, your thinking on a skirt for the blockwork is a good one. Once the slab area is protected from wind chill it's both easier to pour and to finish.
I'd go with the previous advise and power float the slab though if it was me...pinenot

 

[themiddleagedun]

It's best to power float garage floors, it gives a much better-looking finish that will not be always "dusting up"
In summer we concrete 1st thing in the morning, then it's ready to float in the late afternoon. In winter we concrete late afternoon and float next morning. Sometimes it's not gone off enough until later on in the day.
Cold temps. won't harm it, and the cost of the power-float is offset by the lack of need to use a floor paint

 

[limerockconstruction]

Well the temperature stayed good and still hasn't dropped below 3 degrees so i'm pretty happy.

The wind across the land seemed to pick the wet pump mix up pretty quickly and I got a good float on it a couple of hours later.

Thanks for all the advice.

definitely gonna have a chat with people about the power floating next time around though.