Rendering and pva?

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have i started a PVA war here? Well i feel it needs to argued as many people arent sure
 
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I'm sticking to my guns and saying not outside. What other people do is up to them.
 
the answer is, its up to you. i personally wouldnt use it. the last time i did (not my choice, the bloke i was working for was adamant it was ok) was on a full house render over old brick/new block. the old brick got pva'd and the new block didnt. quess which part fell off within weeks. for the sake of a few quid more you get sbr which is actually designed for external work.
 
steve_cov said:
the answer is, its up to you. i personally wouldnt use it. the last time i did (not my choice, the bloke i was working for was adamant it was ok) was on a full house render over old brick/new block. the old brick got pva'd and the new block didnt. quess which part fell off within weeks. for the sake of a few quid more you get sbr which is actually designed for external work.
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will remember that one
 
If the weather is fine and your working on a good background ie brickwork,blockwork why would you whant to use pva.Never render over painted surfaces unless it has been chipped of with a scutsh hammer or scabbler then SBR stipple, apply sratch coat,then top off .
 
broonster said:
If the weather is fine and your working on a good background ie brickwork,blockwork why would you whant to use pva.Never render over painted surfaces unless it has been chipped of with a scutsh hammer or scabbler then SBR stipple, apply sratch coat,then top off .
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Yes I know, but stippling SBR over painted/glazed surfaces, dont know if i would rely on the SBR stipple to support 20mm of render, probably EML it or key it
 
Rendering with PVA

Here goes to the best of my knowledge the only reason you can't use PVA outside because getting it wet re-activates it. So if you are rendering over it with a damp proofing agent included (SBR for example) Then you shouldn't have no problems. Same internally the reason you wouldn't use PVA as a bonding agent for tilling directly on to plaster board is due to any moisture getting through would be a nightmare, especially in bathrooms. SBR is also a bounding agent, just more costly, but a lot better to use (for example on old stone rendered walls) I only use PVA internally i have no idea if frost affects it out doors, sure you can look this up somewhere on the net though. As for the use of paint, with Both PVA and SBR all you need to do is put a scraper over it to remove any loose paint. Then apply directly on top. Simple. Don't use PVA externally above the render to simply apply paint on. I also never apply render onto old render thats been pained, best off knocking it off and starting from scratch. All the best. Please if anyone disagrees or has anything to add to this please let me know..

I've only been building for 2 years and they've all been private property renovations
 
Freerider said:
dont try and be clever, I was using bonding as an example, but tiles have no problem sticking to all three or those backing plasters.
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last lot of tiles i had to chop off had been done onto browning i had to get kango out to get em off lol
 
I have used very week watered down PVA when rendering on old brick work (not painted) many times before and as far as i know there have been no problems . It has been an interesting thread and from what has been said i think i will have to rethink things in the future. but thats what i like about this forum ,26 years in the trade and every day is a school day which goes to prove that you are never to old to learn and just shows how methods differ around the country. What did we do before the interweb?
 
I used to have to hide porn under the bed, now all I have to do is delete the history. Tis great. Don't use pva outside as it will liven up waaaaay down the line, just like this thread.
 
Grump dont be fooled and think just because you delete your history that it removes all traces of what you have been masterbating over ,just ask anyone who fixes computers ,its all still there in the hard drive:RpS_scared: .so be carfull if you ever have to take your pc back to curries you don't end up doing a Garry Glitter:RpS_laugh:.
 
whatever happened to a good old slurry coat? or spatterdash or scudd coating? , 1 sand 1 cement, no pva no sbr, works everytime. They do it everywhere else in europe and particulary ireland. sticks to everything and creates a good base for your render coat. If your sand & cement is not stuck properly to your substrate it will crack as it will move about on the surface.
 
beader said:
Grump dont be fooled and think just because you delete your history that it removes all traces of what you have been masterbating over ,just ask anyone who fixes computers ,its all still there in the hard drive:RpS_scared: .so be carfull if you ever have to take your pc back to curries you don't end up doing a Garry Glitter:RpS_laugh:.
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Not if you use Instant Cleaner Pro!
 
Can you use this instant cleaner pro to make sand and cement stick? and if it falls off/cracks can you use a recovery programme?!:RpS_thumbsup:
 
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