Priming New Plaster

[moodyman]

I have just had my house replastered and now plan to paint the freshly plastered walls. I have a couple of questions that I would appreciate advice on.

Firstly, I have received conflicting advice as to what to use as a primer. My plasterer recommended using watered down PVA but since then I have been looking about the internet and the general consensus seems to be using a watered down non-vinyl matt with a paint:water ratio of about 3:1. Which is correct?

Secondly, I know that the plaster is supposed to be bone dry before priming but assuming I am using watered down paint as a primer I don't understand the point of waiting for the plaster to dry to then just put the water back into the plaster with the primer. I was under the impression that the paint prevents the water from escaping to the atmosphere causing all sorts of problems and if the paint does allow the water to dry then what is the point in putting the water in the paint in the first place?

I hope these questions don't make me sound too stupid but obviously I just want to get the job done properly without any problems. Thanks in advance.

 

[Bodgeitandleggit]

First of all let it dry out completely as painting over when still wet will cause problems later on with flaking/peeling which I have since found out,the use a mist coat with matt emulsion -2 parts paint 1 part water and give it a couple of coats

 

[Nige F]

I have just had my house replastered and now plan to paint the freshly plastered walls. I have a couple of questions that I would appreciate advice on.

Firstly, I have received conflicting advice as to what to use as a primer. My plasterer recommended using watered down PVA but since then I have been looking about the internet

I hope these questions don't make me sound too stupid but obviously I just want to get the job done properly without any problems. Thanks in advance.

I can`t believe your plasterer said that . NEVER prime finished plaster with PVA. it will make it virtually impossible for any emulsion to stick to the wall - then the only remedy would be coating with water based Zinsser @ £40 for 4 liters . Not stupid at all but do let the plaster dry thoroughly - to light pink all over

 

[opps]

matt emulsion will allow the plaster to dry (albeit slowly), whereas silk will not.

The plaster dries from the outside inwards. the long wait is to allow the deeper moisture to escape.

When you prime with watered down emulsion a little of the water will suck into the plaster before the whole of it evaporates outwards.

The final result is that the level of suction (porosity) is reduced, providing a key for the other coats.

PVA will make the surface almost impervious to moisture, meaning the the paint will slide and take ages to dry

 

[Richard C]

My plasterer recommended using watered down PVA

I can’t believe your plasterer said that either no spread I know would advise that; it's really bad advice & will cause you serious problems as already stated. Either he’s not a spread at all or you seriously ****ed him off in some way & he wants to get his own back on you.

If it’s just a skim, let it dry for 10 days then apply 2/3 coats of watered down (25-30%) matt white emulsion in quick succession, dry overnight & then apply your chosen finish. If the plaster work includes a base coat & skim, it could take up to 4 weeks before you can paint it. It may look dry but there is still residual moisture content & painting over it will seal this in leading to adhesion problems & sometimes blistering.