Render on Breeze Blocks????

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johniosaif said:
only use SBR outside, normal pva can add to the problems,,
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john i only use a light coat to damp down the hs/blocks during hot weather!if we get any ,the key to getting render to stick to thermal blocks is soak them big style as im sure you now ,internally probably better and not many use them now any externally as they are crap !!aint seen them external for a while ? there all concrete newton ,personally i like a nice finished brick :RpS_wink:
 
plasmaniac said:
john i only use a light coat to damp down the hs/blocks during hot weather!if we get any ,the key to getting render to stick to thermal blocks is soak them big style as im sure you now ,internally probably better and not many use them now any externally as they are crap !!aint seen them external for a while ? there all concrete newton ,personally i like a nice finished brick :RpS_wink:
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I still see them in extensions, makes no sense to use them but they still do, I think celcon advise against soaking them and using pva,but a lot of spreads have had problems with this type of job and we all do what works for us..
 
Never used pva outside ( absolute No No in my books). Cement destroys pva. But if suction is an issue outside, surely suction is an issue inside regardless of weather out or in and still has to be accomodated for ???????
 
We used rendaid on a job that was all brick. Mixed in a bucket with drill then coated on and run the roller over it. It left a great key to work on, and as hard as the road. I think it is dear but a great product.
 
I've said this before many times on here but here goes again.
I rendered many times onto Celcon/Thermalite blocks without any issues. No scudding and definitely no soaking of the blockwork.
Use correct mixes with added fibres and make sure that both coats cure slowly. I never use lime in the base coat or waterproofer in the top.

If it's cracked after a year then my guess it's the substrate that's cracked not the render, if render is going to crack it usually goes quite quickly in my experience.
 
Hi Andy, It seems we work similar but i always add waterproof to top coat unless using lime. Why do some spreads not use in top coat?? In my opinion it still needs to be plasticised, waterproofed and slowed down. Dont tend to get many issues internally on celcons, just the odd crack occasionally ( like under a window or top of frame, stress points, even if eml is used, mainly cos of weakness in blocks). Never soaked blocks as this provides no adhesion and keying of blocks would need to be done , also pvaing blocks first is like rendering on glass. I dont use lime in backings but back to the question, why no waterproofer in top coat??? cheers, CM :RpS_thumbup:
 
Hi cademan, I always use lime in the top coat and most waterproofers don't mix well with it. I will add some Febmix to the top coat though if I feel it's needed.
 
I only tend to use it in top coat when patterning and panelling ( hands cant take it any more!!!!! and latex gloves are just as bad):-)
 
cademan said:
Hi Andy, It seems we work similar but i always add waterproof to top coat unless using lime. Why do some spreads not use in top coat?? In my opinion it still needs to be plasticised, waterproofed and slowed down. Dont tend to get many issues internally on celcons, just the odd crack occasionally ( like under a window or top of frame, stress points, even if eml is used, mainly cos of weakness in blocks). Never soaked blocks as this provides no adhesion and keying of blocks would need to be done , also pvaing blocks first is like rendering on glass. I dont use lime in backings but back to the question, why no waterproofer in top coat??? cheers, CM :RpS_thumbup:
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If you use a water proofer in the top coat and you get crazing or cracking the water will get in between the coats and that can blow the top coat off in frost. Also in summer if the top coat dries out fast you can wet it down for the next few days to help curing. If it has water proofer in it and it dries out fast well that's it you are snookered.

Have a look around the cracks and establish the fault such as expansion or stress. If the weak area are around the cracks could it be water has got in the cracks and cause frost damage?
 
Rigsby said:
If you use a water proofer in the top coat and you get crazing or cracking the water will get in between the coats and that can blow the top coat off in frost. Also in summer if the top coat dries out fast you can wet it down for the next few days to help curing. If it has water proofer in it and it dries out fast well that's it you are snookered.

Have a look around the cracks and establish the fault such as expansion or stress. If the weak area are around the cracks could it be water has got in the cracks and cause frost damage?
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cheers rigsby, so u advise against waterproof in top coat???? If no lime in top coat, what would u use (just a plasticiser??) regards CM
 
I always use an sbr slurry internal and defo external had agg in the past .if I go 5-1-1, I do put a tiny drop of waterproofer in the top coat of render outside, more to help me spread the gear on as I'm getting older :RpS_thumbup:.
 
cademan said:
Never used pva outside ( absolute No No in my books). Cement destroys pva. But if suction is an issue outside, surely suction is an issue inside regardless of weather out or in and still has to be accomodated for ???????
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Pwhen ur using s+c inside u generally float/devil up a single coat as it picks up. By floating you 'suck' the water back from the blocks back in to ur render. The floating action 'pulls' the moisture back into the gear.
externally I always scud although I have to admit I've never tried Rendaid
 
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