Concrete shuttering with sbr advice.

22 Jan 2017
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United Kingdom
Hi all just a quick question to all the people that know this field. I am about to start a concrete shuttering of a wall that's stepped in only about two inches. Anyway this walls gets a bit damp and before I begin concreting I was told to sbr as a primer and then concrete while it's still tacky, the thing is I've never ever use sbr before and would like some advice on this product for my scenario if possible.

All I want is to waterproof the existing wall before I apply the concrete mix and don't know if I should apply sbr neat or diluted?

Also while I'm here what ballast to cement ratio should I use for a 2inch shuttering on an internal wall?

Thanks in advance.
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I think you may be creating a mess rather than a wall. How is your concrete going to be attached to the wall?

Sbr is a bonding agent and is not a substitute for waterproofing.

You will have to make it very slack to fill such a thin shutter. 10mm absolute max size but 6mm might be better if you can get it.

The other issue is the sbr will make the concrete stick like hell to your forms so be sure too keep them free from it and take them off as early as you can or they might peel the concrete off with them.
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Sbr was advised by a builder to help until I have the outside render redone. I have repaired the render now but sbr is going to used as a precaution. No water gets in at all now and no damp has appeared since. The wall has been prepped with stainless steel hooks to help bond to the brickwork. When I say 2" that's not all the way though as it's measured 3" in places too but mostly 2.5" if im being honest. I did try and get the small 6mm flaky chippings but I couldn't source them anywhere and had to result getting 10mm.

Also what do you mean by sbr sticking to my forms? Do you mean the shuttering boards?
I forgot to mention I will be doing this in stages 36" a time.

The size of the fill is about 1300mm wide by 2.2m heigh.

I don't want to add sbr in the mix just to prep the wall with it before concreting I just don't know the correct method. I would ask my builder friend as he knows what to do but he's away on holiday and I can get hold of him thus me asking here instead.
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If you get sbr on your shuttering it will encourage the concrete to stick to it which is not what you want.

Normally I use 3 parts water 1 part sbr and some cement added also. This can be painted on and ideally your concrete would go in while its still tacky within an hour or so.

Obviously you will have your shutters set up already so dribbling it down the wall might be your only choice, perhaps a foam roller on a long radiator handle?

Id be intrigued to see your setup and the finished result if you didn't mind posting a few photos?
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Also be careful, it Is almost impossible to remove sbr stains from most surfaces once dry so sponge clean any spills immediately.

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