Painting New Plaster - HELP!!! DESPERATE!!! Advice Needed

[igiveitup]

Can anyone help? recently had two rooms plastered, one a skim over the other boarded and plastered.

The skim over room has had at least 10 week's to dry out, after doing a 50/50 first coat on the boarded ceiling, the paint was not adhering to the plaster. So decided to pva 1-5 parts water on the skim over room ceiling.
The emulsion - again watered down is not going on evenly? it's sticking in places and in others it's like map stains coming through.

Have never seen plaster work like this before OR ever had this problem, the emulsion was contract matt which is supposedly for New Plaster, I've tried sanding the ceiling and going over again, which it's still doing the same v.patchy with the emulsion building up very thick around the patch making it look worse.

When I wipe it with a damp cloth the paint comes off on the cloth, even though it's been on for at least 8-10 days.
Could the plaster be contaminated? it's very patchy, could the PVA the plasterers used be coming through? could it be an additive that's been added to the plaster to stop it going off?
OR is it the contract matt emulsion - which has big lumps of pva in it? I've even tried running the emulsion through a sieve after stirring throoughly

I'm tempted to undercoat the patches now that I've sanded them again, but one decorator said you shouldn't use undercoat on a ceiling, nor should you use pva on new plaster either?

Has anyone had or got this problem? any advice on how to correct it would be much appreciated.
Ta

 

[ban-all-sheds]

Lining paper is your friend.

 

[noseall]

You should not put pva anywhere near skimmed plaster prior to painting.

All that will happen is the roller will slide about and no paint will be laid onto the ceiling.

you may have to sand the ceiling or line it with paper as Bas suggested.

 

[Alastairreid]

It sounds like it has been over polished and your advice was correct you should not have used pva on the new plaster.

 

[joe-90]

Oil undercoat. Don't sand it. Don't use lining paper (painted wallpaper)

 

[roughcaster]

Oil undercoat. Don't sand it. Don't use lining paper (painted wallpaper)

That's what i'd do in this case, oil based undercoat it as Joe says,, you can the emulsion on top of it without any problem. It may take each coat of emulsion a while longer to dry, but you'll still get a good finish. As the other guys have said,, NEVER use PVA on new plaster before painting.

 

[landyandy]

.

 

[flameport]

OR is it the contract matt emulsion - which has big lumps of pva in it? I've even tried running the emulsion through a sieve after stirring throoughly

Paint should not have lumps of anything in it.
If it does, throw it away and buy some decent paint.

 

[igiveitup]

Hello,

Firstly thank you all very much for your constructive advice
The contract matt emulsion was bought from a reputable very large builders merchants, told it was good stuff?

I had also bought a gallon of crown solo one coat emulsion as a finish coat.
Had two rooms plastered, attempted one room ceiling with no pva or sealer used. Tried it with a 50/50 watered down mist coat but the paint (contract matt) was sliding about and wouldn't adhere (the plaster wasn't polished as the plasterers knew I would be painting it) if anything it was quite a rough finish.

Because of the problems with that room ceiling, I left it - thinking the plaster wasn't dry enough and went onto the skimmed over room, bearing in mind a good 10 week's had passed.

I rang around a few places - paint manufacturers, decorators supply shops etc ( should have come on here first) asking for advice and enquiring what to use on new plaster - was told by a reputable decoraters supplies to use pva 5 parts water-one part pva - as that's what decorators used. Also told this by various other people (not decorators) infact, when I explained re the plaster, nearly everyone said use the pva to seal it.

To cut a long story short and in sheer desperation, yesterday I sanded all the ceiling taking some parts back to the pink plaster as the contract matt had gone on very patchy - thicker in some places and not covering in other places.

Had in mind to use undercoat on the pink plaster patches, but still felt unsure so decided to check with another decorators prior to doing anything, especially after spending hours sanding by hand!

The helpful chap knew exactly what I was describing re the paint and plaster and said the contract matt wasn't the best for the job. I was told if I used undercoat that I would have to do the full ceiling with undercoat. And then perhaps cover with some good eggshell or an acrylic paint.

OR don't use undercoat and mix pva but this time 15 parts water to one part pva and go over the full ceiling with that and then cover with a good quality emulsion.

Decided to try a couple of pink plaster ceiling patches with undercoat first, then the other two walls that hadn't been painted I tried the crown solo one coat and guess what? it went on like a dream having been watered down, still odd patchy parts with the plaster though, but overall it covered well - when dry I tried the cloth with just water and the crown didn't come off - the contract matt having been on for days and days rubbed off.

That led me to try the 15 parts water to one part pva mix which I rollered onto the walls painted in contract matt - guess what? All the paint came off in patches, with the walls being back to pink and thin coats of white in places - will try to take a photo and add it for people to see.

If this doesn't sound daft, the walls felt better . So after a tremendous stressful 10 day period and many hours of struggling.
That's the situation for the moment - plan to see if the walls will cover with the crown solo and if the finish is good, then I'll do the weak pva - water mix on the ceiling.

Sorry for the lengthy book!!! Will try to add a photo and let you all know the final outcome.

 

[igiveitup]

You should not put pva anywhere near skimmed plaster prior to painting.

All that will happen is the roller will slide about and no paint will be laid onto the ceiling.

you may have to sand the ceiling or line it with paper as Bas suggested.

I didn't use a roller at first used a paint brush on the first room ceiling with no pva or anything used, just a 50/50 watered down coat.

Have since found out the contract matt has latex or pva already added - perhap's that was the lumps?

 

[igiveitup]

OR is it the contract matt emulsion - which has big lumps of pva in it? I've even tried running the emulsion through a sieve after stirring throoughly

Paint should not have lumps of anything in it.
If it does, throw it away and buy some decent paint.

Have since found out that contract matt has latex or pva already added - so perhap's that was the lumps.
But yes I agree, having tried crown I think the contract matt only added to the problem with the plaster.