New Plaster Problem - help needed please!

[Celiar0]

I am new to this forum so hi to everyone and I would be grateful if someone could help with the problem I have.

About six months ago I had a professional company to fit a brand new swanky bathroom for me and I decided I didn't want floor to ceiling tiling so had the walls left bare, new plaster (skim), except for the obvious necessary areas for tiling. I told the fitter to leave the walls for me to paint as I felt this was a job I could manage and I would enjoy putting the finishing touches so to speak.

The fitter did offer to prepare the mist coat for me on the walls and ceiling and to put the final coat of white matt emulsion (provided by me) on the ceiling, which would make the job considerably easier for me to manage, as I'm not as fit as I was, and I gratefully accepted.

I have always considered myself good at DIY and a mist coat to me is a cheap white matt emulsion watered down 5 to 1 with just that, water.

He said he had added PVA to a white trade emulsion, don't know if he added any water. I'd never heard of this being done but I assumed he knew what he was doing and I didn't touch the walls for many months afterwards as I was ill.

At the beginning of this week I started trying to paint the walls in a good quality coloured matt emulsion suitable for bathrooms. However the paint was not covering well and the majority was streaking or sliding off the paint and pva mix beneath, despite several coats.

Things went from bad to worse when two days ago I had the idea of buying the same colour normal matt emulsion to paint on to try to give the surface a bit of 'grip' before I was going to overpaint again with the better quality stuff and it did seem to cover much better.

Today I decided to have a look at what paint he'd used to mix the pva with as he had left the tub by mistake after he finished the job and I find that it is a trade emulsion but it's vinyl silk!

I have always been told never to use vinyl silk to paint bare plaster walls and so suspecting what would happen I went back to the walls with a dampened cloth and sure enough the last paint I have used simply washes off so presumably would the ceiling emulsion but I haven't dared try that!

I've done a bit of research on the internet and I realise now that it's not a good idea to use pva on bare plaster and I would guess that together with the vinyl silk emulsion I've got a double whammy!

Question is, what do I do now?

I don't want the problems I've been reading about on the internet where paint cracks or peels/blisters off somewhere down the line and I don't want a 'sticking plaster' job done either. I need to solve the problem properly now.

Interestingly the young man who did the job is to call back again on Monday to put a new handle on the shower cubicle for me hence my asking the questions now.

I would be grateful for your advice.

 

[geraldthehamster]

PVA should *never* be applied to a wall that is to be painted, as it prevents paint from adhering. Your fitter has bsggered the whole thing up by putting PVA in the mist coat. I'm sorry if that's not much help, but it's the likely cause.

Cheers
Richard

 

[misterhelpful]

It's that old chestnut again.

I made a post a few weeks back that explains how best to seal new plaster but obviously it's not much use to you now. However, if you take a look at the link, you will see that it's not really true that you can't use Vinyl Silk to seal it, although it would be the last choice of product.

//www.diynot.com/diy/threads/mist-coat-or-pva-bare-surface-basics.425261/

I have tried to find out the best way of dealing with existing PVA'd surfaces from paint manufacturers but nobody will give a definitive solution.

This is a quote from one reply I got from Zinsser, which may be of interest to you (and others):

Thanks for your enquiry.

I think part of the problem with there being very little guidance on this subject is that no-one wants to stick their neck out and say they have a product that definitely works.

I have suggested using Gardz to seal in PVA in the past. The Gardz is a great sealer, it’s main use is to seal in wallpaper paste residues allowing you to paint over walls where wallpaper has been stripped.

The only other option which is not particularly practical is to sand off the PVA.

The Gardz is certainly worth a try. It is a thin clear sealer, apply straight out of the can. You then apply an emulsion paint straight over the Gardz.

Note this suggestion is only suitable for walls and ceilings. Where PVA has been used on concrete floors the Gardz could not be used, we would have no products suitable for use on a floor over PVA due to the high wear a floor paint system will be subjected to.

I would also make the point that PVA is a generic name used for many brands of this type of adhesive, applying the Gardz to a test area would be advisable to check the suitability.

I can speak from personal knowledge that Gardz is a great product but can't say I've used it over PVA so, as suggested in that quote, it may be worth testing it to see if it works. Other decorators have used thinned oil based undercoat over PVA, with varying degrees of success, but on large areas it can cause an issue with fumes. Other than that, sanding it all of is probably the only option and will be a nightmare.

Whatever you decide to do, good luck.
mrH

 

[geraldthehamster]

Other than that, sanding it all of is probably the only option and will be a nightmare.

Whatever you decide to do, good luck.
mrH

It sounds like it ought to be the fitter's responsibility to sort it out, as he's the one who put the PVA in the paint.

Cheers
Richard

 

[Bosswhite]

Years ago one used to still come across walls and ceilings painted with distemper (theres still a few about)

I used to clean off and give the walls ceilings a coat of Stabilising Solution prior to Emulsion.

Anyone tried this on PVA painted plaster walls would it work ??

 

[misterhelpful]

Years ago one used to still come across walls and ceilings painted with distemper (theres still a few about)

I used to clean off and give the walls ceilings a coat of Stabilising Solution prior to Emulsion.

Anyone tried this on PVA painted plaster walls would it work ??

I don't think it would work as Stabilising Solution is designed for powdery/chalky surfaces, which is why it would work for distemper, but can't say for sure. That said, Gardz is basically a form of stabilising solution so who knows??

I've often wondered, but would never suggest trying it, if adding PVA to the next coat of paint to be applied over an already PVA'd surface would help it adhere. Then I remember that it shouldn't be used to bond two non-porous surfaces and wonder if one non-porous surface (the existing PVA'd surface) would allow a wet mix of PVA and paint to adhere to it. If it did work then I presume all subsequent coats on that surface would need added PVA.

I'm sure someone will give it a try...just not me!!

Here in the US there is a product called KILZ Adhesion, which is another problem surface primer that adheres to shiny and glossy surfaces without sanding but, again, it still doesn't state that it can be used over PVA.

There is a market out there for any chemistry students who can come up with a suitable product!!

 

[Celiar0]

Thanks for the prompt replies; I’m really grateful for the knowledgeable advice on this forum.

Oh boy, this is giving me a real headache.

I really don’t fancy putting anything else on top to try to solve the problem when there is, as misterhelpful says, no guarantee that it would work and I could in fact make matters even worse for myself.

I’m in my 67th year and not in the best of health so I know, for a fact, that sanding it all off is not something I am physically capable of doing, especially when I think about trying to get it off the ceiling. Nor do I want to risk just slapping several coats of emulsion on top till it looks ok and hoping for the best. This feels like an insurmountable problem to me.

I am going to talk to the fitter who put me in this situation on Monday when he comes to replace the handle on the shower. It won’t go down well, I know. I will show him the replies I’ve had from this forum but he won’t be convinced he’s got it wrong and I already know what his response will be. He will say that he has always done it this way and has never had a problem with it and that he was trying to do me a favour at the time. Unfortunately I don’t feel he’s done me any favours! I think geraldthehampster put it very succinctly!

Other than that, at this moment in time, I haven’t got a clue what I’m going to do.

 

[dcdec]

Make sure he fits the handle before you challenge him!
If you're going to show these comments to him then please add my weight in agreement to what Mr H, Boss white and GTH have said. Its very poor what he's done but time and time again one reads and hears of PVA being used wrongly. I also agree with Mr H that vinyl silk as a mist coat is not preferable but ok if the plaster is truly dry.
I'd also agree that gardz is probably worth trying, it is a very good sealer.

Good luck

 

[geraldthehamster]

He will say that he has always done it this way and has never had a problem with it and that he was trying to do me a favour at the time.

You will be able to show him the evidence to back up what we are saying, by pointing at the wall.

It's often difficult trying to persuade a tradesmen to fix something that they've done badly, especially when it was well-intentioned.

Cheers
Richard

 

[Celiar0]

It's often difficult trying to persuade a tradesmen to fix something that they've done badly, especially when it was well-intentioned

Yes I agree. It was well intentioned which is why I'm not looking forward to telling him at all.

As I said in my first post he did put several full coats of ordinary Dulux matt emulsion on the ceiling after putting pva on and it looks ok but I know it's only sitting on the surface. I'm sure he will say that if I put enough coats on the walls it will be fine.

I have to try to convince him that it won't

I've actually taken a wet cloth to the emulsion I've put on the walls and it simply wipes off!

 

[geraldthehamster]

If the ceiling looks OK, I might be tempted to leave it be. The paint *might* stay there, as it's not going to get knocked or rubbed.

Other than experimenting with exotic primers that may or may not work, I don't see any way round sanding the walls before re-painting. If you're not up for doing this yourself, and as it was a genuine mistake, maybe agree to pay him a small sum to do it for you, in the interests of fixing it?

Cheers
Richard

 

[Celiar0]

If the ceiling looks OK, I might be tempted to leave it be. The paint *might* stay there, as it's not going to get knocked or rubbed.

I had thought about that but I am going to want to repaint it at some point in the not too distant future. It's got an ordinary Dulux matt on it and I know it won't have 'stuck' to the pva properly. Repainting over the top of it again concerns me.

Other than experimenting with exotic primers that may or may not work, I don't see any way round sanding the walls before re-painting.

I don't really fancy risking putting anything else on top of it of it. I think sanding down is the only thing that will put my mind at rest now.

If you're not up for doing this yourself, and as it was a genuine mistake, maybe agree to pay him a small sum to do it for you, in the interests of fixing it?

I'm certainly not up to doing it myself. I had a go at a small area and it was a nightmare to try to get off. I think it needs an electric sander on it. I do agree that I should offer a token payment and I'm quite willing to do that. What a fair price is though I've no idea. I think it's going to take some doing and don't even know if he will be willing to do it! He's coming at 5pm today so I'll let you know what happens.

 

[geraldthehamster]

An electric sander would make a hell of a mess; personally I'd do it by hand.

Good luck with the conversation, anyway - let us know how it goes, if you feel so inclined.

Cheers
Richard

 

[Grenage]

Electric sanders are the way forward, just tape a wet and dry to the outlet.

 

[Celiar0]

An electric sander would make a hell of a mess; personally I'd do it by hand.

Good point Richard, what grade of sandpaper would you use?

Can just imagine this conversation tonight. Not only am I going to ask him to put it right but I'm going to be asking him to do it by hand as well!