/ DIY concrete laying advice

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gethin_allen on 27 Mar 2013
A bit of a random one for a climbing forum but the knowledge base here always amazes me.
I need to lay a small patch of concrete slab to finish off a repair to a drain in my back garden.
My issue is that the weather has taken a turn for the worse and the temp has dropped to the point that I'm worrying about frost messing up all my hard work.
Does anyone know a what temperature I should consider using a frost proofer additive? if these additives are compatible with other plasticiser/waterproofing additives? and if these additives have any major drawbacks?
The patch in question is a sheltered spot next to the house that will only get light foot traffic and I was looking to do a slab of ~2-3inches deep. The weather forecast predicts it to be ~6 degrees in the day dropping to 1 at night.
Thanks,
Gethin.
woolsack - on 27 Mar 2013
In reply to gethin_allen: Put a duvet over it with a hot water bottle and read it a story at bedtime, should be OK
gethin_allen on 27 Mar 2013
In reply to woolsack:
I was seriously considering using an old blanket and a hot water bottle.
In reply to gethin_allen: Don't lay concrete - it burns your cock...
gethin_allen on 27 Mar 2013
In reply to Submit to Gravity:
> (In reply to gethin_allen) Don't lay concrete - it burns your cock...

Who's talking about chickens?
xplorer on 27 Mar 2013
In reply to gethin_allen:

Use a frost proofer, don't use any other additives the frost proofer will act as a feb. you shouldn't need to plasticise for general concrete use. I've rendered full house's in colder weather.
willriseley - on 27 Mar 2013
In reply to gethin_allen: Use a frostproofer/rapid hardener and get it in when its as warm as its going to get. Make the mix quite stiff so theres less water in it to freeze up and cover it with some hessian sacks and thn plastic so the frost stays off of it but the cement can still gas out (dry).
gethin_allen on 27 Mar 2013
In reply to xplorer:
Sounds sensible I guess, I'll have a look at what I can get hold of.
MaxWilliam on 27 Mar 2013
In reply to gethin_allen:

Do it early in the morning and insulate with hesian/carpet/polystyrene as suggested you should be ok at those temperatures even without frost proofer. Use warm water in the mix. If possible store the ballast and sand in doors overnight.

You need enough water for the chemical reaction, which will generate a little heat itself, so don't make it too dry. A basic slump test is a way to tell if you are about to add too much water, i.e. make a little column of wet concrete if it slumps it is too wet!

The other alternative is extra rapid cement. Which goes off in about 30mins. Though you can't add any additives to rapid cement. Rapid cement is about twice the price but for a small area it doesn't matter much.
andymac - on 27 Mar 2013
In reply to gethin_allen:

if you did your concrete you shouldn`t have had to bother with frostproofer.

1 degree celsius overnight is nothing to worry about.
-5 and I `d be concerned.

dont like adding anything extra to my concrete .

I like me concrete to be 'organic'

bit of mix ,cement (4-1) and water.then mix thouroughly until you have a nice creamy ,perky mix .

Paul Hollywood eat your heart out..

DNS on 27 Mar 2013
In reply to gethin_allen:

If you have no reason to rush, just wait. Concrete below 2 or 3 degrees will be inferior.

Are you sure about the thickness? If it's only 2", even with light foot traffic, it needs a good compacted sub-base.

(I run one of the largest consumers of cement in the UK. Don't rush it and make it thicker than you think necessary. Feel free to ignore though!)
ads.ukclimbing.com
Moley on 29 Mar 2013
In reply to gethin_allen:
I've been trying to finish off building my bridge, need to lay a thin skim of cement to level all the foundations and put the bridge struts on. I've postponed it for a week now and waiting for the weather to turn milder. It's only a short job but I don't want to risk messing the whole thing for the sake of waiting a few more days, and I'm like you - novice concrete mixer!
Very frustrating but think I shall hang on and wait for milder conditions, it is very cold here at night.

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