#askapainter. Many times I have been contacted by customers with newly plastered rooms. In their misguided wisdom they are happy to inform me “oh to save paint I have given the new plaster a coat of PVA”
Sadly despite what many DIY books suggest this is never the correct system. PVA is essentially a bonding coat prior to applying plaster, cement or any two porous surfaces together. I think this fad of applying PVA was imported from our cousins across the pond in USA as they term their emulsion paints as Latex, which gets mistaken for PVA over here .
Best practice for most new or well prepared plaster surfaces being made ready to accept Emulsion paint is to apply a ‘mist coat’ or thinned coat 15% – 25% water of the same Emulsion you’re going to finish with. You can purchase Contract emulsions for new plaster with less Vinyl content to allow the plaster to breathe more, but the process is still the same as you want that first coat to bond with the surface of your wall or ceiling.