Protecting concrete from frost

[elsmore1]

Hello,
I have dug a trench footing for a full height conservatory and now plan to concrete it, any ideas on when is too cold for laying concrete and how to protect it from frost in case I lay it and the weather forecast is wrong. This weekend was the plan but though it should be dry the temperatures are dropping. The footing is about 300mm deep by 350mm wide and will contain a A142 metal reinforcing mesh.

Some of the footing may be exposed as the ground slopes a bit in one corner but when dry I will back fill over with soil, surely concrete can withstand frost as are most concrete drives foundations just normal concrete in this country unlike Alaska.

Thanks

 

[PrenticeBoyofDerry]

Best not to lay it if temps reach zero or below,
you can buy frost resistant admixtures or cover the area with frost blankets/hessian blanket to keep the frost off.

 

[elsmore1]

Thanks for reply, I read from cemex website that it needs to be kept a 5C for the first 48hrs, I also see you can get frost blankets from a foam material probably too expensive or use hessain covers or Bubble wrap!

 

[PrenticeBoyofDerry]

Anything that will keep the frost off, I think 5 degrees is playing it really safe.

Depending on the area and volume/cost, you could think about admixtures to defend against frost or something that may speed the curing time up.

 

[elsmore1]

Yes I think that it must be stopped from freezing for sure but curing times will be longer. I will speak to my local builders merchants to see if they have hessain sheets and advice on admixtures.

Thanks

 

[PrenticeBoyofDerry]

np

 

[hotrod]

It'll be fine elsmore you're worrying over nothing. This weather is mild, unless we have a serious drop in temp then yes, consider frost protection.

Out of interest, what mix are you using C20/30 etc? I still think the re-bar is an un-needed expense but it's your choice so he-ho!

 

[elsmore1]

thank you hotrod, I will be using hessain rolls so it should not freeze and if concrete has its own heat generated than I hope it will be ok, but the temps seem to be dropping with some overnight frost, but not seriously cold, overnights of 0 or just below next week, this weekend I may still be ok with no frost.

 

[elsmore1]

forgot to say it should be a C20 got a all in one ballast from builders merchants and I have already brought the mesh but its was pretty cheap!

 

[elsmore1]

All bets are off! Not risking it this weekend temps are dropping so will wait for warmer weather.

 

[PrenticeBoyofDerry]

coward

 

[Chukka63]

coward maybe,but makes sense