I know when painting newly skimmed walls that I have to do a mist coat first but... some of the walls/ceilings in my house were skimmed and left unpainted for approx 1 year so are dried out. Should I still do a mist coat or can I go straight to using undiluted matt emulsion? Have done a couple of walls with a mist coat but just wondering if I need to.
Absolutely do a mist coat-the drier the plaster the more it'll suck up the water in the paint-I'd use a contract emulsion (armstead etc cheap but not rubbish) 20-25% Dilute otherwise you'll get a flaky, badly adhered, really annoying surface to paint over. Honestly it's really really frustrating picking bits out of your roller.
TommyPurdyPnD states, you should always apply a mist coat when painting fresh plaster, especially when its totally dried out. If you are unsure how to do this, see our painting new plaster project here
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