setting concrete in cold weather

[ARWadsworth]

I have a few posts to set in concrete and the weather forcast says it will be about minus 3 overnight. If I crack on and do the posts in the morning will this be a problem?

Adam

[visionset]

Unlikely to be a problem, the ground is warmer than the surface. A few cm down is usually frost free. Just cover it with something to be sure.

[Peter Lynch]

Some years ago the place I was working had a legal requirement to have a new building commissioned by Dec 31. Much to the annoyance of the (software!) manager in charge of this work, the builders said that they were unable to pour concrete when the temperature was below 2 degrees 2 (that's +2) as it wouldn't set properly.

Personally I'd cover the proposed site tonight (before the frost) and do the work and then put some insulation over the concrete. The temp. is supposed to drop due to clear skies, so the insulation will help keep the ground around the work warm.

Pete

[meow2222]

if you use clear sheet poly, it'll act as a solar panel during the day, and the crete will store the heat overnight.

NT

[Owain]

I'd suggest letting the ground warm up first, and - as it's only a few posts - make the concrete with hot water, and insulate (carrier bags filled with straw, or something, over the top).

It may be obvious from the foregoing suggestion that I really know very little about concrete!

Owain

[The Natural Philosopher]

Or use FEB wintamix in it..that will stop it freezing. which is the only crucial issue.

[ARWadsworth]

I set them at 8 this morning. No frost was present and it will be a good 16 hours before the temp hits zero degrees. I will stick some covering on later though

Adam

[The Natural Philosopher]

Frost will split wet porous brick,. The idea is that the concrete is stronger than porous brick, by the time the frost gets to it ...;-)

Xould be a mater of 2-3 days at these temps.