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Plastering

Im a plasterer and been doing it for 7 years, just reskimmed my bedroom ceiling it was plasterboarded and skimmed ceiling

I APPLIED PVA AT CONSISTENCY OF 2 PART PVA 1 PART WATER BECAUSE IT WASNT THEY BEST QUALITY PVA AND THE CEILING SKIMMED FINE AND IT DRIED OUT AS NORMAL, I THEN PAINTED IT AND THAT TO WAS FINE. NEXT DAY I NOTICED A BIG CRACK AND IT HAD ALL BLOWN AND THE SKIIMING CAME DOWN IN BIG SHEETS ONLY THE NEW SKIM NOT EXISTING CEILING, I NOTICED THAT IT PULLED SOME OF THE OLD PAINT OFF WITH IT BUT BEFORE PVA ING CEILING I CHECKED OLD PAINT AND SCRAPPED IT AND NONE OF IT WAS LOOSE, EVERYTHING ELSE I HAVE SKIMMED IN SAME WAY IS TOTALLY SOUND ITS ONLY THIS 1 CEILING ANY ONE ANY IDEAS WHY THIS HAPPENED?

9 Answers from MyBuilder Plasterers

Best Answer

Hi, sounds as though you didn't score the ceiling before you applied pva especially if the ceiling is painted. New plaster as you should know needs a good key, on painted ceilings we always score before PVA.
Hope this helps.
Bruce

2012-01-30T15:30:02+00:00

Answered 30th Jan 2012

simples!!.. Bond failure. Why use useless PVA... might not be that but sounds most likely. If you are a plasterer why change your normal PVA which is tried and tested?? If its not that its some great unknown. Never happened to me thank God, if you are gonna attempt another re-skim i would key up the existing plaster. Personally i would overboard to be safe, just be greatful its your house and not a customers.

2012-01-30T15:30:02+00:00

Answered 30th Jan 2012

Hi Craig,

It seems almost certain that there is a problem with the integrety of the old paintwork.
I've seen this happen when plastering over old lime based paints - whitewash, etc.
Is it an old building? Is the old paint dry and powdery?
If this is the case, I'm afraid I can't offer a solution, other than overboarding.

I doubt that PVA was at fault.
I've been plastering for over 30 years and still use PVA on painted walls and ceilings.
PVA is very reliable if you know what you're doing.

One other thing, check that the weight of the new plaster hasn't pulled the old ceiling out of shape as this could cause the new skim to fracture and break away particularly on old lath and plaster ceilings.

Either way, I'd play safe and overboard the ceiling next time.

Paul.

2012-02-06T09:30:02+00:00

Answered 6th Feb 2012

It could have been egg-shelled painted if you've plastered directly onto it, even if you pva it's a nightmare. You can't always tell neither but it's very rare. I did a job last year and was told it was silk on ceiling, I plastered it after pva, next day it had blown in bits off ceiling. When I asked customer, he said it could have been egg shell paint he used, turned out it was and not silk emulsion. Egg shell paint is a nightmare. I always know if 100% now it's egg shell reboard a ceiling least then you know they'll be no problems with it after. gareth-martin

2013-07-09T15:10:02+01:00

Answered 9th Jul 2013

Surprised to see that with 7 years behind you you're using PVA on paint,not the ideal thing to be using really to give a 'key' for your plaster..........this could be part of the problem :/

2012-01-30T15:30:02+00:00

Answered 30th Jan 2012

did you miscoat the ceilings. As if you apply paint straight from the tub the plaster will just soak the paint up like a sponge causing the ceiling to dry to quick and then over short time either flake away depending on the heat of the room or simply crack, or in your case which sounds like a bad case just fall off piece by peice.

2012-01-30T15:30:02+00:00

Answered 30th Jan 2012

Hi know one has said the most obvious thing that all plasterers have to look out for when ever looking at a ceiling !!!!
DESEMPER it's a nightmare your pva wood be useless with it ! I have never herd of scoring a painted ceiling before pva 😫 The slightest thin layer would bring your ceiling down in sheets ! So beware. Richard Poole
Pooleplastering.com
http://www.diydoctor.org.uk/projects/distemper.htm

2017-01-29T14:20:01+00:00

Answered 29th Jan 2017

Hi sounds like DESEMPER to me.... That stuffs a nightmare!
Had something similar happen to me years ago Skimmed a ceiling got to 2pm spotted the plaster pulling away.....back in the van off to builder's merchants for 8x4 sheets and more finish 😁... Not a great day!!
I inform the clients when I find it then just overboard ceiling not cheap but there's not much you can do

Always Stick to high grade gules or bonding compounds when plastering! remember if your laying on 2 bags of finish 72kg wet then once dry that's 50kg on a ceiling

Best Regards Steve

2017-05-14T11:25:02+01:00

Answered 14th May 2017

This did happen to me once ,i got my labourer to score painted ceiling and pva it with the client supplied ,then i skimmed no problem .two days later client phoned to say ceiling had a big crack ,so we went over to sort it ,couldn't understand then i took a close look at the pva that was used it was like white water faulty crap pva .
scraped the old plaster off ,it came off in sheets .i redone the lid with my pva perfect ,answer to your question faulty pva ,

2017-10-21T08:15:02+01:00

Answered 21st Oct 2017

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