skimming onto dry PVA - will the plaster blow ?

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mike1972

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Hi - useful forum this

Ive used an electric chisel to take back all the old plaster back to the lime and sand render of a 1930s house. I applied one or two coats of PVA to each room with a liberal coat of 50/50 water/wickes PVA mix and let it dry for a day or two at the most.

I told my builder/part time plasterer that he should plaster onto tacky PVA, he said it didnt matter. I then PVAd again with a 3 parts PVA to 1 part water late the night before as I thought it wouldnt be so dry the next day and would adhere better. The guy then applied 2 coats of thistle multi finish the next day (any big holes were filled with bonding days prior).

The final PVA coat was not 2 hours old tacky but it was still a little soft in the morning (you could scratch it with a fingernail). This was over the last 3/4 weeks so its been cold and damp.

I just got a new proper plasterer in to finish 2 rooms as I wasnt happy with the other guys finish. The new plasterer is saying that if skim went on dry PVA, it will likely fall off once the central heating goes on over winter and it dries out.

Im wondering if its worth bothering with a good paint finish if it may all blow, im also wondering if I should take it all off and get it re-done now before I furnish the house, Whats the consensus please? I would be grateful for your advice...
 
Well mate , I have done it both ways on my own home so long term it made no difference , the skim is sound.
 
well I used a builder who could just about plaster rather than a true plasterer, ive learnt my lesson thats for sure, i just hope it dont all fall off ! Thanks for your responses all.
 
different answers from people, Ive asked different plasterers that ive spoken to who have given different ansers so to solve this one and for all i will update you lot with what happens over the next 6 months, it will either all fall off xmas morning into my mince pie after 2 months of central heating or it may just stay on the wall. Watch this thread...
 
i was always taught to plaster on it while its tacky.you may get lucky.in future let the plasterer do it,if the walls are really dry give them a coat of pva the night before
 
I pva night before, and prior to skimming, as a general rule, as that was I had taught, but have to admit their have been many occasions when have just pva night before, and done so on the basis of working with other spreads I greatly respect , and have many more years experience in the game than me, who said this was ok,
 
PVA re emulsifies when in contact with moisture, so you can skim onto it when it's dried, and then when the skim dries out you re create that same bond between substrate n skim, just thought I'd throw my two penneth in :RpS_wink:
 
UM actually.... bond-it, unibond, etc.... they are all Poly vinyl acetates or copolymers... they all re-emulsify when made wet again. So technically it matters not which way you do it. I was taught do it when its tacky, but in truth it doesnt matter. I think that comes from the whole job n knock thing at the end of the day. Its merely choice.
 
PVA, sealer and adhesive, 1st coat seals to control suction, 2nd coat bonds the finish to the sealed substrate, skimming on dry PVA's like skimming on glass.
 
says on the pot apply plaster when tacky, so all you people that plaster onto dry pva are really taking no notice of the manufacturers recoomendation, if it falls off in a years time , who's to blame ??
better to do it properly or not at all.
 
gordo said:
says on the pot apply plaster when tacky, so all you people that plaster onto dry pva are really taking no notice of the manufacturers recoomendation, if it falls off in a years time , who's to blame ??
better to do it properly or not at all.
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Been spreading 30 odd years sometimes i skim straight onto dry pva, never had a problem and neither have my lads, it boils down to knowing what your capabilities, limitations are and product knowledge
 
ruffdiamond said:
PVA, sealer and adhesive, 1st coat seals to control suction, 2nd coat bonds the finish to the sealed substrate, skimming on dry PVA's like skimming on glass.
Click to expand...
No its not mate if you pva a unpainted wall it'll go off quick it's not just sitting there and not bonding to the surface
 
gordo said:
says on the pot apply plaster when tacky, so all you people that plaster onto dry pva are really taking no notice of the manufacturers recoomendation, if it falls off in a years time , who's to blame ??
better to do it properly or not at all.
Click to expand...

You cant blame any one if you use any BG plaster as they dont recommend pva just there own products.
 
2 coats pva the day before,wickes own brand i use all the time,skim straight on to wall never any problem,all the best.
 
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