p.v,a problems

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0160fliddy

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Hi, people i was wondering if anyones had problems with pva on reskims lately, the stuff dont seem to have any guts no more, roll a coat on the walls leave it to tack up and apply first coat of skim as usual go have a cup of tea for 5 mins come back and the plasters starting to run in places and pva is bleeding through and its nearly imposible to put a trowel over it without draging the plaster off. Ive tried loads of different makes , the only one which is any good is unibond. This started about 12-18 months ago probably 2 out of 5 jobs , no problems for 18 years before that. Anyone got any ideas, cheers.
 
No mate read it about haif hour ago , the walls i am skimming are normall emulsion paint no distemper or nothing like that, i have used stabilizer on some crapy backgrounds but shoudnt need it on normal emulsion
 
If the plaster is running/sagging & dragging with a trowel then the pva has got to be still wet,
that's why it would slide down the wall!
also how thick was the plaster applied when it was sagging?
& what ratio roughly did you put the pva on?

What I'd do is apply a thinner coat of pva because it sounds like it's too thick to me,
& try skimming it when the pva is nearly dry & it won't sag or drag then.
Don't worry it'll rewet the pva back up a bit when you skim it.:RpS_thumbup:
 
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0160fliddy said:
No mate read it about haif hour ago , the walls i am skimming are normall emulsion paint no distemper or nothing like that, i have used stabilizer on some crapy backgrounds but shoudnt need it on normal emulsion
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you're right, in that emulsion should be fine to pva onto and reskim. Maybe it's the substrate underneath that's the problem? I had this on a lime based substrate that I pva'd. Had to put on loadsa coats of pva, and the pva took all day to go off.

nisus is right too, if the pva is too thick and still wet then the plaster won't stick.
 
had the same thing happen but we found that if the pva mix is thicker and applied thinly with a roller the problem is solved.if its silk emulsion then the pva should be pretty much neat anyway.its a nightmare to control when it happens too.british gypsum rep told me we should really be using thistle bond it as much as possible.not sure if it was sales talk but he reckoned it makes all the difference and should be trouble free.fine if you time in advance to apply it.slight design fault imo.
 
Had some fail on me for the first time ever yesterday but it did freeze up over christmas i need to launch it.
 
lol I skim over rock hard PVA I use to wait till it went tack and all that but now I just roll 2 coats on and when its hard I skim, never had any problems what so ever.
 
we quite frequently have done that in the past but the bg rep reckons because pva is to bond the skim to the wall,it must be tacky otherwise the skim has a chance to blow off in the future.we try and do things by the book if poss but the same as you danny,we havnt had any problems and have even skimmed the following day without giving the walls a fresh coat of pva.some walls can even have patches go tacky then dry while other parts of the wall are still wet.cant win.just need to use experience in the end
 
you say the wall has to be tacky.... but the next time you skim a wall when the pva has go off scrape a bit of the finish off and see.... its wet again :-)

I never ever had any problems though... but when I have waited for PVA to go tacky I have often got on it too early and it just goes to a gooey mess.... and then you have the top drying before the bottom and god what a pain in the ass......

I skimmed one wall the other day that was partly board and partly painted, and it all went off at teh same time (which was nice) :-)
 
Danny said:
you say the wall has to be tacky.... but the next time you skim a wall when the pva has go off scrape a bit of the finish off and see.... its wet again :-)

I never ever had any problems though... but when I have waited for PVA to go tacky I have often got on it too early and it just goes to a gooey mess.... and then you have the top drying before the bottom and god what a pain in the ass......

I skimmed one wall the other day that was partly board and partly painted, and it all went off at teh same time (which was nice) :-)
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lol :RpS_thumbup: theres nothing worse than a gooey mess its like trowellin porridge :RpS_laugh:
 
throw the pva in the bin not used it for years
tight coat of bonding mixed with skim 50/50
wait till tackey then skim
throw a couple of handfls of bonding in your skim
it sounds daft but try it
came from a real old timmer
 
as i say it might well work but it shud be "keyed" bonding is gypsum it needs a key. i ve scraped off bonding where yes iy was on the wall but once attacked with a scraper came off with ease in largepieces with a very smooth back.if you want to be 100% sure bonding plaster needs a key on certain backgrounds
 
left a bit on me bucket trowel for a bit long today... had to almost chisel it off... :RpS_blink:
 
Artex sealer is also a good way to go, skim on iit as soon as its dry, normally bout 20 mins,its a bit more expensive , and the set hangs around for ages,but cos you skim it when dry you dont get into a situation.
 
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