The great B&Q PVA disater

[mark]

Just had a room freshly plastered, went down to B&Q to buy some paint. Not being experts asked for some advice, we were told that we should seal the walls with a PVA glue solution before applying our matt white water based emulsion(also recommended by some B&Q employee).....

Got all the stuff, PVA, Paint, rollers etc etc. I mixed the PVA with 5 parts water as instructed and proceeded to coat the walls. Once the PVA solution had dried we started to apply the first coat of emulsion. It was like painting on glass! It took 4/5 coats to get an even cover. Days when the painting was done, we noticed certain bits needed touching up(bits missed, knocks etc etc)...

Started rollering and the paint that's on the walls just start bubbling and pealing off like paper. Not a very happy moment. It's obvious that the PVA solution hadn't worked, as it happened when we were painting ther first coats we decided to not use the PVA solution on one wall just to see how it differed and this wall only needed two coats...

So we call B&Q not very happy with the advice they had given. All the people at B&Q who we consulted all said "you are supposed to use PVA glue to seal walls". The manager then when to check with the decorating expert who also said the same, they then checked out the glue we had purchased (just regular Unibond PVA) and in the very small print it said "not to be used with water based paints"...

We then get a call back from B&Q appologising for being given "ill advice" and they offered more paint yadayada. The biggest DIY store in the country don't know how to put emulsion on walls?

It's two days to xmas and we were supposed to be moving all our stuff back into the "new" room today. Due to bad advice from B&Q we have a room full of flaky paint ontop of PVA glue, one wall is already start flaking like crazy. The others are fine, but we don't know what to do.

B&Q have suggested we go over the paint with oil based emulsion, but surely just putting oil ontop of the water based emulsion will do no good as it's all still ontop of the shitty glue layer. It would take literally days to scrape off all the current paint, and it won't steam off.

Anyone got any advice? at all?

regards

[Stefek Zaba]

Pragmatic: stick lining paper over the duff walls, paint on top of that. Try getting your new friends at Been-n-Queued to supply the paper and Solvite for free (and a 50% discount on the pasting table, scissors, seam roller, and papering brush ;-) Normal emulsion atop the lining paper will still let the plaster finish drying out.

Arsey stand-on-my-rights: try to get your new friends to pay for a decorator to do same. Good luck...

Another time: let the plaster go off (finish the reaction which uses up the bulk of the water - you can see it change colour) - takes a day or so in a heated room, longer otherwise. Use a diluted emulsion for your first coat - wot spreads call a "piss coat" - about 1 part water to each

4 parts paint. (Finally, a use for elcheapo shed-special Brilliant White; at the cheapest end of the market you won't even need to dilute it, as the supplier'll've done it for you ;-) Then paint as normal atop

- again preferring emulsion, not oil-based paint.

D-i-y advice? At B&Q? Well, it's like taking the first reply you get off Usenet - might work, might be total twonk. At least on Usenet you get a bit of "peer review"!

Stefek

[mark]

All the walls are the same aprt from one little bit that we didn't use the PVA on. So far though only 1 wall has started to flake(the wall where we started to touch up, the rest of them still need touching up too....)

It makes me cringe at the thought of putting lining paper on, considering we just paid to have it plastered an' all :-(

not ruled that out yet, im well and truly pissed off right now.

[[news]]

calm down dear, it's only a disaster :)

/devils advocate:

you've been misadvised BUT it did say on the tin "not to be used with water based paints" which you did. it's unlikely that B&Q will afford you a small team of artisans to put your room straight but you may be able to get some vouchers which you can put towards some quality paint with a lot of pigment in it.

FWIW I only ever paint over new plaster, light coat and a couple of decent thick ones usually does it. leave it a few days over xmas until it's all gone off /properly/ and you may be surprised that you can get a light coat of paint on and another a few days later, and so on, until the desired effect is achieved.

RT

[BigWallop]

The only thing I could suggest, is to hang lining paper on the walls before you paint them again. You should really have lined the new plaster in the first place, in my opinion. Painting directly on the wall doesn't leave much scope for alteration in the future. Hanging paper on paint also usually ends in disaster.

Water and PVA solution that can't be used with water based paint is beyond me. You mixed the PVA and water OK, so why did it blister under water based paint, I ask myself. Weird. Although the makers have it on the tin that it shouldn't be used with water based paint, so it must be correct.

[Stefek Zaba]

S'far as I can tell, it's not the depth of pigment that's an issue here, but adhesion. The PVA's had the predictable effect of sealing the surface of the fresh plaster, making (as he reports) the subsequent paint lie loosely on the so-sealed surface, and bubble/peel off when sneezed at (or as local evaporation of residual water in the fresh plaster pushes the PVA-and-paint or paint-where-PVA-didn't-cover off the wall) - a problem which is likely to be made worse, not better, by either putting on yet more coats or covering as B&Q suggested with an oil-based paint, thereby making it effectively impossible for any water to diffuse to the surface.

Hence the dismal pragmatic solution of lining paper. The OP's enthusiasm for scraping off the PVA-n-paint layers is understandably infinitessimal, as would be their chance of doing so without putting gouges into the luvverly smooth new plaster finish :-(

[[news]]

I think the main issue (apart from not RTFM) is not recognising that PVA can take a while to dry, even longer with all that water still in the plaster.

and as for paint, more pigment = fewer coats = less moisture to soak off the underlying PVA / paint mixture which now coats the wall.

to the OP:

leave it for a while, it's xmas, wait 'til it's DRY then try a coat of paint and I'm sure you'll be surprised, the paint will stick, but you still need to persue those vouchers rigorously !

RT

[mark]

It blistered under the pressure of the roller, the original coats had been on for a week but during the work we had a floor fitted and some other work done and therefore there were some scuffs and dirt on the walls. When we started to apply the "touch ups" with the roller the peeling started.

[Christian McArdle]

I never understood this PVA advice. I know it is given all over the shop, but I can't imagine it ever being other than a complete disaster. To seal new plaster, use Dulux Trade Supermatt, diluted down. I wouldn't even consider letting PVA anywhere near fresh plaster.

Sorry for posting such a useless response, though. I have no idea how to recover the situation.

Christian.

[Stuart Noble]

"Christian McArdle"

PVA is essential on old plaster but a newly "polished" plaster surface is pretty dense, and IME doesn't require sealing. In fact, you need to dilute the emulsion to get it to penetrate the shiny surface. Maybe the OP's plasterer incorporated PVA into his skim to provide a good surface to paint on, and the 2nd coat has oversealed it and formed a skin. Five coats on top of that and you're looking at a skin you could peel like an orange. I wonder how easily the whole lot would lift off with a bit of steam and a scraper.

[John Rumm]

(BTW, Unibond is a very expensive way to buy PVA!)

Was this a waterproof unibond PVA? Might be part of the problem....

[:::Jerry::::]

The manager then when to check with the decorating expert who also

And you can't read either by the looks of things, don't you ever read instructions or are you just terminally dim were painting is concerned ?...

[mark]

we did read the directions prior to painting, but not the small print. Considering we had the tin virtually put in our hand and were given the directions verbally it wasn't at the forefront of our minds to read the entire contents of the label print on each tin.

I realise your point is valid, and looking back it was a mistake on our part. In future maybe you should talk to people on usenet as if you were talking to them in real life, it's all very clever 'talking shit' anonymously hiding behind a keyboard, it must be very rewarding. I don't think you'd talk to me that way face to face, unless you enjoy getting your face smashed in on a regular basis.

[Lobster]

Tell me about it - I had just the same situation myself some months back (and asked the same advice here as well!) I'd always used dilute emulsion myself in the past, but this time it was the actual plasterer who advised me to use PVA. Pratt.

To the OP - I don;t think my problems were as bad as yours sound, but in my case, the 'mess' did seem to stabilise after some days, so suggest you don't take drastic action just yet!

David

[Michael Mcneil]

It sounds to me like you did more than mix the pva with water. A PVA mix (or just neat PVA) on glass or formica will allow you to paint or plaster over it as soon as it is dry. Every one knows that. Even the staff at B&Q. You would have got the same advice here from most. (Except me and Lobster.)

I would have said just use trade emulsion (the really cheap stuff) and not to bother with PVA.

If you add anything else to the mix, you have what is called a "release agent". PVA mixed with meths and water is used on resin casting molds to give a layer of impervious -almost non stick, friable skin over the polished surface.

Try it out for yourself on a formica work top. Mix a small batch of clean water and pva; one with a drop of paint in it; some with some meths or rubbing alcohol and some with almost anything else as a control.

The only one to stick will be the water/pva mix.

I think you owe the staff at B&Q an apology.

[mark]

By the sounds of it I'm sure it would be worth it.

[mark]

really, we didn't. It was just 1 part PVA to 5 parts cold water, applied to fresh plaster with a brush. What else do you think we did to it?

[Stefek Zaba]

Interesting conclusion. The OP specifically asked them for advice, presenting hisself as a novice; and they gave it - as I understand it, they actually chose the particular "PVA" - maybe a PVA with additives - for him. That, coupled with the fact he's actually *had* an apology from Been-n-Queued, quite strongly suggests the direction of due-apology is BnQ -> OP, not t'other way around...

[Dave Plowman (News)]

Did it appear to soak in, as a matter of interest?

[mark]

yes, it was just like putting water on really, soaked in within a few minutes