Painting newly repaired plaster/skim containing PVA

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Hi all,

A plasterer recently performed quite extensive repair/infill work on some of our partition walls and elements of the ceiling. He used PVA when skimming. It's nice and smooth but not overly polished.

The PVA extends to around 6" outside of the repaired areas and there is bare skim within that. The skim is quite thick and was applied in two stages. It has fully gone off.

Nomally over bare plaster I'd use a mist coat of trade matt, but I'm concerned that if I do so, I'd reactivate the PVA leading to a mess. Considered Bullseye 123 but it's water based. Also considered BIN, but not sure if shellac is appropriate here and its very expensive.

Rather than spot prime, my plan was to thin some solvent based undercoat (Leyland) and apply it using a short pile roller to all walls/ceilings affected with PVA, in their entirity, to hopefully produce an even finish with subsequent coats of vinyl matt. My understanding is that I would need to allow the solvent based undercoat to go off fully (around 7 days) before applying any water based paints over it.

Am I on the right lines with this approach? I would appreciate any advice.

Thank you
 
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The oil based undercoat should be fine but I would only use it on the PVA.

Would you not be concerned about a patchy finish if I apply only to the visible PVA? It would mean I was painting the outlines of squares in the centre of some walls, if you see what I mean.
 
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Would you not be concerned about a patchy finish if I apply only to the visible PVA? It would mean I was painting the outlines of squares in the centre of some walls, if you see what I mean.

If you are using decent emulsion, it shouldn't be a problem.

I should have added that the emulsion over the undercoat will take much longer to dry. Take that in to account when rolling, do not over roll those areas because if you do you risk the roller "pulling" some of the emulsion (just applied) off. That will lead to inconsistent coverage.

You probably won't need to wait 7 days before applying the emulsion. The next day "may" be OK. Fisheyes are more likely when painting over finish coats such as oil based eggshell/satinwood/gloss. I have had fisheyes in the emulsion (cutting in) when using poor quality paints such as Farrow and Ball 7 days after the oil based eggshell has been applied.

Personally, I would use shellac based paints but primarily because the cure time is about 40 mins. If you aren't in a rush, the undercoat is equally good.
 
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You can paint over thinned pva. It's only neat plastering pva that can pick up and cause problems.
Acrylic primer undercoat will be fine over.
Also use beeline primer which is pva type product.
Gardz will also be fine.
Depends what paint you using tbh.

I'd just stick the acrylic primer over then dulux heritage or johnstone's durable acrylic or similar
 
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You can paint over thinned pva. It's only neat plastering pva that can pick up and cause problems.
Acrylic primer undercoat will be fine over.
Also use beeline primer which is pva type product.
Gardz will also be fine.
Depends what paint you using tbh.

I'd just stick the acrylic primer over then dulux heritage or johnstone's durable acrylic or similar

Hi Wayners

I'm not sure if the PVA is thinned or how it was prepared. I tried to sand it, but 120 grit just squeaks over it and makes no progress whatsoever, not even gumming the paper.

I think the solution here is going to be a test patch and try the two options suggested by you good people
 
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Think you over worrying tbh.
Just crack on with it would be my advice.
 

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