Help with Ocr.

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jerry.j

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Help with Ocr.
Hello, we have had a complete nightmare with this. Last year we bought a pft ritmo m. We went on the course . And not really used it since. On Friday we started to spray a new build with webers ocr, it went on loverly no problems. We sprayed on and staffed off then waited for it to pick up then floated and sponged. It looked amazing. Today we went to it and both gables are covered in cracks with some small parts blown. Completely at a lost. Any help much appreciated thanks.
 
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What I've found with both weber OCR and mono is it pulls in quick on blockwirk
OCR does micro crack and I tried every trick in the book to stop it.
Hose the work down at the end of the end which might help
I use k rend gp mortar now which is 2 coat work
 
Yes the background is block work, and the thickness was between 10 and20mm.
It was all sprayed and staffed by 11 and floated and sponged by 3.30 . What preparation to the background would you recommend ?
Thanks for replying.
 
bobby said:
What I've found with both weber OCR and mono is it pulls in quick on blockwirk
OCR does micro crack and I tried every trick in the book to stop it.
Hose the work down at the end of the end which might help
I use k rend gp mortar now which is 2 coat work
Click to expand...
Have you used Parmurex yet mate?
 
jerry.j said:
Help with Ocr.
Hello, we have had a complete nightmare with this. Last year we bought a pft ritmo m. We went on the course . And not really used it since. On Friday we started to spray a new build with webers ocr, it went on loverly no problems. We sprayed on and staffed off then waited for it to pick up then floated and sponged. It looked amazing. Today we went to it and both gables are covered in cracks with some small parts blown. Completely at a lost. Any help much appreciated thanks.
Click to expand...
 
What background was it on if it was a new build what newton blocks were they anything less than 7 newtons two passes with mesh and rend aid first
 
ocr will do this and weber will give you a list of things u shouldov did.. move on and use and equivelent material.
 
Thanks everyone for your replies. I think it must have dried in too fast. We are going to test it again with wetting the block first and maybe a light mist last thing . Thanks again for your help.
 
jerry.j said:
Thanks everyone for your replies. I think it must have dried in too fast. We are going to test it again with wetting the block first and maybe a light mist last thing . Thanks again for your help.
Click to expand...
Wetting before and after will help, but the easiest thing to do to eliminate it is pull a drop film down from the soffit once you finish an elevation, the moisture can then not escape and cause the shrinkage.
 
Becareful how you wet blocks down. Flood them just before or even a few hours before and you will get water seeping out on the horizontal joints. That will cause the mortar to ripple on the horizontal joints.

As above 7 newton blocks, in two passes and cover the work up as you progress.

You may still get cracks due to slumping.
 
Is parex ocr equivalent any better? I've got a job on blockwork coming up and I was gonna rendaid 1st to help with the suction?

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It's basic rendering and coz it's called one coat render people think they can use it as such on any background. It's this complicating plastering business that's been going on for a while, with these new materials and tools on the market people are becoming plasterers overnight. Like what rigs says give it a coat to control the auction then turn back and top it, it is basics that seems to get lost on this forum because they either think a magic trowel will sort it or they have a machine. This is the main thing we were taught in our apprenticeship and that was how materials work and how to treat every background, when things go wrong and why. This sadly is missing and people rely on a forum for advise and an excuse, this is basics it has dried to quick, I'm not having a dig at the original poster coz I see it on here all the time, it really is basics.
 
flynnyman said:
It's basic rendering and coz it's called one coat render people think they can use it as such on any background. It's this complicating plastering business that's been going on for a while, with these new materials and tools on the market people are becoming plasterers overnight. Like what rigs says give it a coat to control the auction then turn back and top it, it is basics that seems to get lost on this forum because they either think a magic trowel will sort it or they have a machine. This is the main thing we were taught in our apprenticeship and that was how materials work and how to treat every background, when things go wrong and why. This sadly is missing and people rely on a forum for advise and an excuse, this is basics it has dried to quick, I'm not having a dig at the original poster coz I see it on here all the time, it really is basics.
Click to expand...
A fair point.
 
flynnyman said:
It's basic rendering and coz it's called one coat render people think they can use it as such on any background. It's this complicating plastering business that's been going on for a while, with these new materials and tools on the market people are becoming plasterers overnight. Like what rigs says give it a coat to control the auction then turn back and top it, it is basics that seems to get lost on this forum because they either think a magic trowel will sort it or they have a machine. This is the main thing we were taught in our apprenticeship and that was how materials work and how to treat every background, when things go wrong and why. This sadly is missing and people rely on a forum for advise and an excuse, this is basics it has dried to quick, I'm not having a dig at the original poster coz I see it on here all the time, it really is basics.
Click to expand...
Have to agree with some of your points there although I've been rendering for a few years now and I had a job where I tried everything to stop these micro cracks.
Covering the work would be the best solution although it's not possible sometimes
My job was a few hundred metres on 7n blocks.i was told it is being caused by it drying to quick.
I gave the blocks a light damp down,used sbr prior to rendering and even covered the scaffold with sheets to protect and still had problems
I've now gone back to using bagged render using it the old way,scratch coat then top
Not had any issues with k rend gp mortar and have used around 2000 bags this year to date
 
jerry.j said:
Yes the background is block work, and the thickness was between 10 and20mm.
It was all sprayed and staffed by 11 and floated and sponged by 3.30 . What preparation to the background would you recommend ?
Thanks for replying.
Click to expand...
I would say also 20mm is probably to thick
I use 10mm beads dabbed on giving 15mm max
Two passes at around 8mm
 
flynnyman said:
It's basic rendering and coz it's called one coat render people think they can use it as such on any background. It's this complicating plastering business that's been going on for a while, with these new materials and tools on the market people are becoming plasterers overnight. Like what rigs says give it a coat to control the auction then turn back and top it, it is basics that seems to get lost on this forum because they either think a magic trowel will sort it or they have a machine. This is the main thing we were taught in our apprenticeship and that was how materials work and how to treat every background, when things go wrong and why. This sadly is missing and people rely on a forum for advise and an excuse, this is basics it has dried to quick, I'm not having a dig at the original poster coz I see it on here all the time, it really is basics.
Click to expand...
Even Weber say that on the thickness
 
I've never used OCR because of the stories on here about it, I normally scratch coat, then base coat full mesh silicone 1.5mm finish. Not everyone can afford this system so I give them mono (Parex) not much more than OCR price wise. Or just cpi traditional way
 
Said on the fb page the other day. Bobby on a full load parmurex was about 5.50 a bag. 30kg must be similar pm to gp
 
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