I am decorating a room from scratch after it had been replastered. Before I started, my granddaughter painted in green poster paint (I think) on the bare plaster. I have used B and Q value emulsion as a primer and B and Q Colours white silk emulsion over the top, I guess I must have gone over the area about 4 times. I just cannot hide the marks. Does anyone have a suggestion please (apart from don't let kids paint on the wall!)
various options - use a stain blocking paint such as Zinsser Bullseye or a shellac based primer. alternatively you could lining paper the wall.
a normal (good quality) solvent based undercoat may work - the poster paint may be a solvent paint as well.
another option is to use (with respect!) a better quality paint such as Dulux Vinyl available in various finishes. B&Q emulsions are not exactly top quality and lack the opacity and stain blocking of superior products.
Firstly, when you used the value emulsion as a sealer did you water it down to form a "mist coat" - anything from 15-25% water depending on quality (consistency) of emulsion ?
If not watered down it may effect the bond between the new plaster and emulsion and lead to flaking of the finished painted surface
I would suggest that you give the problem wall a quick rub over with 180 grade paper and then wipe down with a damp cloth, frequently rinsed out
Buy Dulux Trade White Undercoat (this is an oil based undercoat) and give the wall 1 coat using a short/medium pile roller
Follow the drying times on the tin and allow plenty of ventilation - as oil based it pongs !
If the green paint is still highly visable, give a 2nd coat of undercoat
Once dry, 2 top coats with your emulsion and that should solve the problem
Dulux is much more expensive than the B&Q stuff but is quality in a tin
Hi, I would do similar but instead of putting just the oil based undercoat on the wall I usually mix equal quantities of oil based gloss and undercoat together and paint this on. I find that having the gloss in with the undercoat it covers better. Then if It is only a couple of patches I would just cover them and not do the whole wall as oil based paints do smell a lot. If it bleeds through this then use an aluminium primer on it or one of the others mentioned by previous posters. Once dry give the patches a coat or 2 of emulsion and allow to dry then do as the others say and use Dulux emulsion as it is much better than the cheap ones. It covers better so usually needs fewer coats, gives a better finish and is washable not like some of the cheap ones. So it can actually work out cheaper in time and money.
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