Using SBR in mixes

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Rigsby

Rigsby

TPF Special Forces
I have been reading several manufacturers specs on render mixes mixed with sbr. It sounds like using a sharp sand and cement mixed with 2 1/2 - 3 ltrs of sbr per mix will give a polymer modified render which is waterproof.

I did a job a couple of years ago mixed with neat sbr and it was as creamy as f!*k and seemed to set ok. It was a one coat experiment at the back of a garage.

Has anyone used sand, cement with 2.5-3 ltrs of sbr per mix and found it ok? I am trying to make my own polymer modified mortar to hopefully save cost on the likes of ocr and C+G etc.

I have done a couple of screeds but with neat sbr. Sticks to trowels and straight edges like bugger if you are not fast with the water brush.
 
Have done external render wit sbr in the mix but not on that large a level,found that it was clumping when scraping it back so wouldn't use it like that again.but use it for a bonding agent in the most extreme circumstances.good gear.
 
I'm interested about this aswell, I'm not sure if it was Henry or Warrior that recommended sbr for w/proofing, i personally have never tried it for this purpose, would like to hear more about this please yodas :RpS_thumbup:
 
Sbr is a good polymer i have used it at 50/50 to water for mixing this is probably the highest ratio i would recommend as 40% of the mixing liquid needs to be water to fully hydrate the cement, also because there is little water in the mix it needs to be kept wet to fully cure, you could add cellulose to the mix to soak up water and keep the mix wetter for longer but you will struggle to get hold of it however i can supply it i can also get hold of redispersible polymer powder which is what all the big manufacturers use aswell as superhydrophbic powders for waterproofing. You may want to think about using fillite instead of sand as it is 1/3 the weight of sand and wont slump these are the standard raw materials that are used in most basecoats
 
Been useing sbr today in rendering found it heavy going mix felt dead when spreading warrior never told me how to fluff it up. I suppose that's His trade secret.:RpS_thumbup:
 
When adding large amounts of sbr it should be mixed with a drill rather than a cement mixer as its not aggressive enough
 
DannyMac said:
Would this ratio make a scratch coat fully waterproof?
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Not waterproof, but water resistant, I would not use the term waterproof when specifying,

Henry I thought I'd told you you need forced action an not a standard cement mixer, we rarely use a belle mixer when were modifying mixes
 
warriorupnorth said:
Not waterproof, but water resistant, I would not use the term waterproof when specifying,

Henry I thought I'd told you you need forced action an not a standard cement mixer, we rarely use a belle mixer when were modifying mixes
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I've been looking at these for mixing lime hemp. What is a good make? Which one do you have?
 
Personally I only use SBR as a primer, never in my mixes because of cost and integral waterproofer will do the job in most situations.

If you want waterproof you will have to tank.
 
Interesting about the water content? I have been looking at different manufacturers and on average 2.5-3 ltrs per mix is about the max. In summer with dry sand a mix can take 15 ltrs of water so 3 ltrs is = to 20%. A did a small job recently with 3 ltrs of sbr in a full Belle mixer and it was nice stuff to use, just slumped a bit more than usual.

I have a semi to do in a couple of weeks so I will let you all know how I get on.
 
Yes I realise that but why would you use SBR in a render mix when you could just use Waterpoofer?
 
Not so much the waterproofing but the flexibility. Finish is to be bucket coat. SBR slurry with two coat render modified with sbr and mesh embedded. Really don't want any more cracking after the trouble Weber got me into last year. I have done a scratch coat topped woth Weber ocr and I got a bit of air bubble-ing. Just wondered if anyone had done sbr modified with two coats and any suction or air bubble-ing?
 
What do you mean by SBR modifying.....:RpS_confused:. ive never heard that term b4 and im now intriged
 
My thoughts are that using a modified render with SBR may well work but you wont get a guarantie as you would with a dedicated waterproofing system.
 
lucius said:
My thoughts are that using a modified render with SBR may well work but you wont get a guarantie as you would with a dedicated waterproofing system.
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You wont get a garuntee anyway the manufacturer will say its not installed correctly if it fails
 
CKJ said:
Sbr is a good polymer i have used it at 50/50 to water for mixing this is probably the highest ratio i would recommend as 40% of the mixing liquid needs to be water to fully hydrate the cement, also because there is little water in the mix it needs to be kept wet to fully cure, you could add cellulose to the mix to soak up water and keep the mix wetter for longer but you will struggle to get hold of it however i can supply it i can also get hold of redispersible polymer powder which is what all the big manufacturers use aswell as superhydrophbic powders for waterproofing. You may want to think about using fillite instead of sand as it is 1/3 the weight of sand and wont slump these are the standard raw materials that are used in most basecoats
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So how does it work on a 1&1 slurry,no water involved?
 
not sure what your on about m8, but any render is only as good as the background and prep before it. Imo a sand/cement render with waterpoofer is sufficient, if you want to put mesh in fine, but really don't see SBR making that much difference, its cement at the end of the day.
 
Sbr can make one hell of a difference, but as said previously I have put some major specs and how to's on this as well as tanking etc and really don't fancy re typing it , so if no one else can be bothered to search or paste links to the threads etc, neither can I
John if you want to talk render modification then pm Ckj
 
lucius said:
No comment on the washing up liquid bit though
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Washing up liquid is a surfactant and is a fantastic air entrainer making a fluffy creamy mix. surfactants are common additives for cement based mixes most manufactured air entraining additives are surfactant based.

As for slurries i wouldnt recommend using neat sbr anyway the ideal slurry would be 50/50 sbr-water 1 cement and 1 sharp aggregate either sand or glass keep substrates damp not wet and work on the slurry whilst still tacky
 
Didnt want to get involved in this again but i will, under a microscope the bubbles in , lets call it fairy liquid are irregular sizes against Febmix lets say where all the bubbles are the same size this creates different size air pockets in the Fairy morter causing it to break down in time which ive seen to many times also on the side of a Fairy bottle there are no instuctions on how much to add to a S&C morter mix and Febmix is cheaper so why would you use something not designed for the job on something as important as morter.
 
warriorupnorth said:
Sbr can make one hell of a difference, but as said previously I have put some major specs and how to's on this as well as tanking etc and really don't fancy re typing it , so if no one else can be bothered to search or paste links to the threads etc, neither can I
John if you want to talk render modification then pm Ckj
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Paul - You can't search 'SBR' cos it's too short a word :)
 
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