Painting already PVA'd bathroom ceiling-I think I need help!

[TheFive]

Hi All,

Just signed up as there seems to be a wealth of expertise and experience on here that I'm hoping will help stop me having to post on the DIY disasters board!

Ok, the background is this - moved into a newish house (10yrs old) a while ago and started on a bathroom 'refresh' project which obviously includes some painting tasks. Existing paint on ceiling and coving was in good condition and didn't really need doing at all but I thought I'd do it anyway. Painted with standard Dulux matt emulsion (pretty sure the existing finish was also matt) and disaster struck. Within days ALL the paint started to peel off (as in not just the freshly applied stuff but down to bare plaster/coving). The coving was particularly bad, ceiling less so but was still coming off in quite a few places.

This was left for a period and then I went back to it and prepared the surface as far as possible by removing all the flaking paint and sanding back as far as possible, but only in damaged areas. The paint that was still sound was left in place.

Next step, based on some 'advice' I got was to seal the ceiling and coving with PVA. Not sure what the ratio was as my dad did it but I'm guessing he followed the instructions on the tin. Now having looked on here it sounds like that may not have been the best of ideas. The PVA tin clearly states that painting with Emulsion is not recommended - doh!

So, not sure what to do next. I've got some Dulux Trade Eggshell (solvent based) ready and waiting but having read the data sheet it appears that this stuff is probably also not suitable for the job, and once it goes on I expect that getting it off will be extremely painful.

So, anyone got any evidence/experienced based ideas on how to proceed? I'm actually ready to start so any prompt assistance would be hugely appreciated!

Cheers all!

 

[Zampa]

My guess is that you have put the paint on too thick and over the top of contract matt..which is a lot more absorbent than vinyl matt

Forget the PVA...

All the action is going on between the old coat and the new...so no matter what you put over it youl still going to have a problem.

You should try and scrape it ALL off and start again..if thats not possible you really need to get the latest coat off...maybe soaking with really hot water and scraping will do the business for you

 

[TheFive]

Thanks for the advice Zampa. I think getting all of this stuff off will be nigh in impossible without sanding back to bare plaster. I will not be able to tell the difference between the old paint and the new paint, and to be honest I couldn't even see the difference when it went on... so I guess getting off only the new paint = full sand back to bare plaster!

When you say that all the action is going on between the old coat and the new, what do you mean by this?

Prior to PVA'ing, the new stuff never seemed to be coming off on its own (i.e. it was never leaving the old paint behind). It was either all cracking down to bare plaster and all coming off (old and new together) or it was sound (most of the ceiling is actually ok; the coving was badly affected).

To be honest the PVA went on a month ago or more and the surface now seems stable - there has been no additional peeling or cracking since the PVA was applied. Sticking down tape and ripping it off isn't pulling any paint off either.

My theory is therefore that the surface is now sound but that I have a compatibility problem with the PVA and the paint that I would like to use (emulsion).

Following some more thinking about this I have a suggestion, which may or may not be pushing the boundaries of science:

How about priming with Dulux Trade Primer Sealer (solvent based so in theory should have no issue with being slapped on top of PVA), then finishing with a couple of coats of Dulux Trade Diamond Eggshell (which is apparently OK for painting onto solvent based painted surfaces and is pretty moisture resistant)?

My thinking is that the only potential flaw with this plan is that the primer may destabilise the PVA in some way causing everything to come off... again

Any thoughts?

 

[TheFive]

Just some additional clarification as I guess it's important for me to give a clear description of the problem:

When the new paint went on, it adhered to the old paint very well. There are no areas where only the new paint has come off on its own. Where the paint has failed, both old and new paint have peeled off together leaving bare plaster behind.

I guess something that hasn't helped is that I left it to deteriorate for quite some time before trying to tackle the problem. So where the paint started to fail and expose bare plaster, moisture/condensation was able to penerate behind what may otherwise have been sound paint and over a long period of time (9 months?) it slowly kept on coming off bit by bit, making quite a mess.

I am thinking that when the house was built, the original plaster wasn't properly primed and in places the original paint did not get a chance to bond properly. Painting over it again was maybe just enough to cause the bond to fail in a few places. Not addressing the small number of problem areas for ages resulted in further deterioration....

 

[Zampa]

The original painter might not have put a mist coat on..which causes a similar problem as yours when you painted over the contract emulsion..

If it was contract emulsion...

You mention about the original coat coming off too...it might also be down to the plaster on the ceiling being 'polished' when it was plastered.

Putting a water based paint over PVA could/will reactivate it