I need to paint what used to be a (wood?) boiler room which over the years has accumulated a thin layer of black on the brick walls and rendered ceiling. I have cleaned as best I can - no loose stuff, but still pretty black.
How best to tackle this? Should I seal/stabilise first with PVA or some other product? Should I then use indoor immulsion or a masonary paint? I did just put a dab of exterior masonary paint onto the surface and it seemed to take OK. The quality of finish is not important as is only to be used as a store cupboard.
Any advice appreciated.