The great B&Q PVA disater

[Stuart Noble]

"Michael Mcneil"

I think in resin casting circles, PVA stands for polyvinyl alcohol. Can't envisage any situation where polyvinyl acetate would act as a release agent

[Stuart Noble]

Well, exactly. IME pva (including the paints based on it) sticks to itself rather well. I think maybe there are 2 things going on here. Pva formulas are getting better and maybe the product needs to be diluted more. Paints (particularly Dulux) are getting more non-drip so that women in dresses can paint the ceiling when they've got a moment. They get the extra thickness by adding mineral extenders (chalk, clay etc) and IME this makes the product virtually unuseable on any surface.

[Christian McArdle]

That certainly doesn't apply to the Dulux Trade Vinyl Matt or Supermatt. I'm quite disturbed how good these paints are compared to others I've used. On fresh plaster, I put down a diluted sealing coat. When it is dry, the wall already looks fine, and barely needs the main undiluted coat at all. So much for the recommended sealing coat and two top coats. It would just be a complete waste of time putting 2 top coats on.

Christian.

[Rick Dipper]

Sandpaper ........... alos know as one of the worst DIY jobs in history. You loose that lovley fine surface you just had put on. I'd talk to the platerer, who will look down on you, and maybe sort it all out for you .......

My plasterer told me never to seal the walls, but to use water based paints that don't make a film to let "his" plaster aretwork dry.

Like any other company B&Q are just as good as the people they employ, and like any other job, 50% of them should be doing something else. They were nice to you, so you didn't make any bad publicity .....

Rick

[Brad]

Look at it from the retailers perspective.. I work for one these "sheds".

Trying to get clear advice from anyone is not easy (except on this newsgroup.. which is why I keep an eye on advice here). I've worked in retail 15+yrs but that doesn't mean I'm an expert in all things diy.. nor should I be expected to be a qualified decorator, plumber electrician gardener etc..

I think it's unfair to blame this on B&Q. If you look at the tin of PVA it clearly recommends using it as a plaster sealer and tells you how much to dilute it down. B&Q also sell Dulux and own brand plaster sealer, whether this is any different I do not know. Therefore it's natural for anyone to assume that PVA is suitable for sealing plaster. The manufacturers are covering themselves I guess by putting a warning about not using it for water based paints. I used to recommend the PVA solution before and never had anyone coming back with a problem. I'm guessing it depends on how dry the plaster is as I always told customers to ensure that it was dry.

I think the manufacturs should give clear advice... try phoning Dulux on their help line and they will tell you to use their own plaster sealer .. naturally. Will they tell you to ensure the plaster is dry first? .. no.

I've asked several decoarators who I've seen in store.. they all give different advice.. so how can a non tradesman be expected to know.

What I have learn't is that you MUST let the plater dry out first.. many people seal the moisture in which causes problems.

The best solution as far as I know is to use TradeSupermatt.. sadly only the B&Q warehoue stock this as the smaller supercentres do not stock trade products. I've even pointed this out to my Dulux Rep.. who had no idea and was telling my staff to recommend using plaster sealer. It was only thanks to someone a whle ago on this newsgroup that I had the specification sheet to had clearly recommending it for use as a sealer. I've asked Dulux to expain why the give different advice to Trade and DIY users and will let you know what response I get.

I hope you can see from this that it's unfair to blame this on "some dim-wit working for minimum wages" giving you shitty advice.

Brad

[Stefek Zaba]

Unseasonal as it seems, that's where I put the blame - though not just on the individual, but on B&Q as a corporate entity. They sell themselves as a place to not only get products but advice - the warehouses are full of (often correct ;-) boards with "How To..." advice, there are "Project" leaflets at the exit (aren't there?), they employ people supposedly with trade experience to give advice.

And in this case, they've palpably failed. The combination of their employee selection, subsequent training, and market positioning has ended up with this customer following the advice given, buying the products suggested, applying them as advised, and ending up with a significantly unsatisfactory finish. Case closed! It's not a "hanging" offence - which is why I didn't suggest the OP had much of a case for getting the whole problem fixed at B&Q's expense (as he would've done if this cockup had been made by a decorator engaged by the OP); but apologies (which were issued) and further supplies to remediate would feel equitable to me.

Stefek

[Nick Atty]

I've been really impressed with Wickes Trade Brilliant White Matt (I'm well into my 4th 15-litre tub of it). Diluted very slightly (about 1+4) it goes onto new plaster a treat, and the one coat is certainly livable with - it doesn't look thin or streaky. It also makes a great undercoat for the coloured versions.

[Michael Mcneil]

If you didn't add paint or something to it then the plaster must have been sealed too soon.

Sorry and good luck.

I don't know the correct ins and outs for making mold release but just try mixing anything with dilute pva and see if I was wrong in my original post.

PVA mold release is the colour and smell of meths mixed with dilute PVA glue.

[Steve Firth]

Way too much PVA to be used as a sealer. At that concentration I doubt that it would have soaked into the wall at all. It's some time since I did it, but ISTR that when using PVA at glue strength, you need to dilute it 1:30 to 1:100 to use as a sealer for plaster.

[Steve Firth]

I can't envisage any situation where the polyvinyl alcohol sold by Unibond (and others) as wood/general purpose glue would be described as polyvinyl acetate.

[Brian Sharrock]

I was very sorry - and even scared - to read of your troubles ...

We too had extensive 'decoration' done to our front room in the run up to Christmas.

The entire room wasn't replastered, but as each wall had channelling for new electrical outlets, and the walls needed in-filling for dings, gouges and picture-hook fixings et al; each wall had lots of patches that needed smoothing out. I too went the B&Q route (receipts to hand) and followed their advice. The walls were coated with PVA-dilution -allowed to dry- had a coating of white 'water-based' emulsion - allowed to dry- then finished with (Dulux) emulsion mixed-on-the-spot top colours. The effect is beautiful. When I read your post, I was _scared_ ! Was I going to experience your problems ... ? Scurrying to the garage to find out what I'd bought ... it was 'EvoStick' PVA! Why did I buy EvoStick PVA -from B&Q- rather than UniBond? I dunno ... it was just _there_; no conscience decision made at all.

Sorry this doesn't advance your case ... but at least I'll read the maufacturers' blurbs more closely and make sure ...'it does what it says on the tin'.

[Rob Nicholson]

Except when tiling.

Rob.

[Dave Plowman (News)]

I'd always thought that PVA adhesive and emulsion paint had a similar base anyway?

[Steve Firth]

Could be, I'm afraid that the chemistry of paint is well beyond my capabilities. The same recommendation goes for new plaster IIRC, that emulsion paint should be applied to bare plaster as an extremely dilute wash before applying the top coats.

We painted the place in Italy using a "breathable" emulsion. And the recommendation from the supplier was to stabilise the old plaster using an extremely dilute PVA solution (1:250) and to allow that to dry for a day before applying a first coat of emulsion diluted 1:30, then to use the paint at 50:50 dilution after that.

For soem reason all paint in Italy needs diluting before use. It took me by surprise, but I think it's because the DIY market is non-existent. If you want a house painted you engage a painter, and they stick to the good old fashioned ways of expecting paint to be supplied at 2x working strength. My wife tried using gloss paint out of the tin, and it was a minor disaster. Needed rubbing down and repainting using a 50:50 dilution with white spirit.