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Painting & Decorating

Has our 'mist coat' gone wrong?

Hi. I know painting on plaster is an often asked question but we hope you might be able to give advice for the mess we have made...

Two weeks ago we had the walls and ceiling of our living room plastered by a plasterer who we think did an excellent job (he was plastering directly onto the brick work of our chimney breast and on to plasterboard every where else). He advised us to wait 3 to 5 days before doing a mist coat of 50/50 paint / water. We waited 8 days and painted using Farrow & Ball Primer & Undercoat, mixed 50/50 with water. The next day, patches appeared of flaky paint (one patch of flaking paint where it looks like we had painted more thickly, and the others mainly on the corners where the ceiling meets the wall or on the inward facing corners of the walls).

We are wondering if this means we used too much/too little water, if we should have waited longer for the plaster to dry or if we painted the mist coat too thickly?

And then we are wondering what to do now... if we can just sand those areas and apply another mist coat to those areas and continue with the the other coats, if we should apply a second mist coat to the whole room or if we should just leave it all be for a few weeks to dry as perhaps we should have done to start with.

Any advice would be much appreciated. We have asked a few people and have had conflicting views so far.

3 Answers from MyBuilder Painters & Decorators

Best Answer

First of all did you plaster man use hard wall on the bare brick first and then a top coat.of finishing plaster.

did you use the correct Farrow & Ball Primer & Undercoat as there is more then one.
I would never use F&B primer it really is not needed, all you need is standed Dulux emlusion for a undercoat, you cart always say its %50 %50 mix as this depends on the paint, its really done by eye, What I would do going forward is rub the wall's down and use a cheap standed paint 50/50 would be about correct, if you put it on the wall and you cart see plaster still its to thick, but you have to be careful as if you put to much water in it you will not leave enough paint on the wall.

As long as the bare plaster is light in colourand no dark patch's you are ok to go.


Answered 4th Nov 2012

Paint will definitely peel if plaster is wet
you would never get this problem if dry.
even if you don't mist coat the paint should not peel because the plaster is
like a sponge when its dry.


Answered 9th Feb 2016

Farrow and Ball is one of the worst paints on the market. It is thin anyway, requires more coats, and is super expensive. I always recommend customers steer clear. So many colours are available now that any F&B colour can be painted on a piece of wood and colour matched at a Dulux shop for half the price.


Answered 18th Feb 2018

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