painting onto primer on a plaster wall General decorating topics, questions and answers. find help, tips and advice on completing your decorating projects

[lat42]

had a small area of wall bricked up then covered with a cement mortar and a finish of plaster. Just a ready mix type I think, and it was dry in 2-3 days. I then coated it with a general primer with a view to coating it with emulsion. The primer has given a sheen like finish which the emulsio just runs off...what next???

[stoneyboy]

lat42,
You will have to repaint the wall with an oil based undercoat but try a small area first to check the is no reaction with the primer coat.
end

[rosebery]

What did you use to "prime" the plaster?

[lat42]

i used an all purpose primer, suitable for use on newly plastered walls

[rosebery]

OK I'll rephrase the question. SPECIFICALLY what did you use to prime the plaster?

[rigga]

lat42, There should be no need to use a special primer on this new finished plastered surface and do not use undercoat as recommended by stonyboy, as the wall has had a backing coat of sand and cement this wall will be alkaline by nature and this will saponify the oil in the undercoat and will lead to problems later. If as you say you have used an all purpose primer then this should be okay but don’t use emulsion straight on top, after rubbing down, use a coat of water based acrylic primer which will adhere better than emulsion and is more flexible you should be able to emulsion directly on top of this.