Is there a special method of painting over a water stain, after my boiler leaked through the ceiling?
Your stain will keep coming through any water based paint. PVA is water based and it will come through that too. You use any oil based paint to seal the stain back. Proper decorators will use an undercoat as is has a matt finish – noone wants to be emulsioning over gloss. Professional ‘stain blockers’ are unecessary and often don’t work as well as undercoat – which has worked for me everytime in thirty years.
