Priming New Plaster

[emeritus]

I have just had some walls and a ceiling replastered and its time to decorate now. What is the best method of preparing the new plaster for a final coat or two of emulsion. The plasterer said to use PVA / Adhesive but I have read that is not advisable. Grateful for any advice.

[Old_Geezer]

I've used PVA, it seals ok but I felt the residue was noticable. Why not just water down your first few coats of emulsion ?

[bookbinder]

Old_Geezer is quite right. The instructions on the side of a tin of emulsion should tell you how much water to put in for your first coat on new plaster.

[emeritus]

Thank you both very much I will have a go at that. Although I am doing the walls and ceiling in colours I suppose I could use some watered white emulsion as a sealer/primer ?

[bookbinder]

I can't see anything wrong with using white. You might end up with a slightly paler version of the final colour, but nobody will notice.

[The Builder]

I wouldn't use PVA, Emeritus. It's not good to "seal" new plaster. It has to dry out completely before it can be painted. Make sure it's completely dry simply by keeping an eye on the colour. It'll be quite obvious when all "tide marks" have receded.
The other (technically pedantic) reason for avoiding PVA, is that a first coat (mist coat) of emulsion should sink into the plaster for a good key. This coat should be thinned (far more than they say on the tin - almost 50%).

If I were to be annoyingly correct, all new plaster should be painted with "Contract Trade Emulsion". It's non-vinyl, thus breatheable, but please don't worry about it. When the plaster's dry, carry on as above.

[emeritus]

Thanks very much Builder. Someone else mentioned Trade Emulsion to me. I am grateful for your advice. Just off to the shops, need to get started on it this week-end

[theshedman]

Hi emeritus, listen to The Builder never use PVA it will cause problems when you go to paint on it. The PVA will seal it but then stop the paint from bonding with the wall as the paint will try to bond with the PVA and this will cause bubbling. The copy below is from an e-mail off another site from a decorator fed up with being asked this question and so asked Dulux themselves. Hope this helps you make your mind up what to do.

Thank you for your E-mail I can categorically confirm we DON'T Recommend using PVA to seal new or bare plaster.This is because the PVA will seal any residual moisture on the plaster and may cause bubbling when it dries.This is also stated in the BS 6150 and our ICI site work instruction.

[emeritus]

Thanks Shedman thats really helpful.