Painting on new plaster

smcqis

I have just got the plaster on my chimney breast done. It was just one days work with skimming over plasterboard and was wndering how long I should wait before painting this

nickj_2

once it is dry should be fine - you can tell by the colour of the plaster , if it's got any damp patches they will be darker than the dry areas
don't forget to paint with a mist coat of matt emulsion (thinned , 70% paint 30% water ) on the bare plaster

smcqis

We have an undercoat type paint that says its suitable to go on to masonary and plaster, would this do the job straight on and paint it in our emulsion colour after

nickj_2

not sure what that is , but masonry paint is for exterior
if you have some old matt emulsion kicking around just use that or just thin a bit of the paint you are going to use for the job

greenlaws

Plaster on a chimney breast.. Why was it taken off? I suspect you'll have the same old problems back again soon. You cant put gypsum plaster over a chimney breast which has salts and derived damp issues - it needs to breathe.. I ask the question again - why is it replastered. Look at the original problem, look at what came off, and ask yourself - is the same thing again going to cure the problem.. probably not. It should have either no plaster, and raked / repointed in lime brickwork, or lime plaster that can breathe.

nickj_2

greenlaws wrote: »

Plaster on a chimney breast.. Why was it taken off? I suspect you'll have the same old problems back again soon. You cant put gypsum plaster over a chimney breast which has salts and derived damp issues - it needs to breathe.. I ask the question again - why is it replastered. Look at the original problem, look at what came off, and ask yourself - is the same thing again going to cure the problem.. probably not. It should have either no plaster, and raked / repointed in lime brickwork, or lime plaster that can breathe.

have you actually read the original post - it's been skimmed over plasterboard -

martinthebandit

As others have said you can paint over it as soon as its dry. The reason posters are advising you to use a first coat of watered down emulsion is that the first coat just soaks straight into the plaster so you are saving a bit of paint by watering it down.

To be honest though, if its just a chimney breast I would just slap the emulsion straight on as the amount you will save is minimal.

Your going to need at least three coats mind and paint is one of things that you get what you pay for.

Leif

martinthebandit wrote: »

As others have said you can paint over it as soon as its dry. The reason posters are advising you to use a first coat of watered down emulsion is that the first coat just soaks straight into the plaster so you are saving a bit of paint by watering it down.

To be honest though, if its just a chimney breast I would just slap the emulsion straight on as the amount you will save is minimal.

Your going to need at least three coats mind and paint is one of things that you get what you pay for.

The reason for watering down the first coat of paint - the so called mist coat - is that if you applied neat paint, the plaster would suck the water out of it so quick that it would dry before it had a chance to permeate into the wall. The result would be a layer of paint on the surface with a weak bond. By applying a mist coat, you ensure that the first layer has bonded well. The next layer then bonds well to the first layer of paint.

If you don't believe me, try it with a small patch of bare plaster. The paint should scrape off easily once dry and cured. This is also the reason why you must prime walls before applying tile adhesive.

Incidentally, according to many people who know far more than me, some cheap paints are so watery that they do not need watering down when used as a mist coat. Dulux paints tell you how much water to add when doing a mist coat. I assume Crown et al do too. I used 20% water with Dulux emulsion.

googler

Plaster Sealer from B&Q as opposed to 'mist coat'?

Saves having to do any mixing....

slipperyshoe

googler wrote: »

Plaster Sealer from B&Q as opposed to 'mist coat'?

Saves having to do any mixing....

Not money saving though! just use any old paint sat in the shed (throw out old paint after 3-5yrs though as it will be no good for anything). Water down 50-50 IMHO.

mandragora_2

Oh, leave it for a week and just enjoy the lovely colour, and how fabulous it all looks at the moment. I LOVE newly plastered anything!