Patchy when painting ceiling

[matthlock]

Hi, I'm redecorating my bathroom and am having problems with painting the ceiling. It was originally covered by polystyrene tiles which I have removed and steamed/scrapped off the adhesive, but some of the paint on the ceiling flaked off leaving patches. I've sanded down the ceiling and given it several coats but the patches where the paint flaked are still showing through. The patches seemed to dry with an orange peel raised texture with a bit of an off-white colour but seems a bit better this morning (although still has the raised texture).

I'm not sure what else to try. The paint I have is about 2 years old and a budget brand, so wasn't sure if buying a new better one would work better?
Do I need some special primer? I have acrylic wood primer, would this work? Will I need a skim (trying to avoid as I can't do it myself)? HELP!

 

[footprints]

It's differing substrata the bare areas needed priming and painting to achieve the same texture as the old paint.
Cheap paint will not help either, if you want a guaranteed answer to a good smooth surface put up lining paper, chances are it is only a little ceiling and two coats of good quality paint something like Dulux diamond matt.

Otherwise just keep applying coats till you build up a smooth even texture

 

[matthlock]

Thanks mate.
I bought new paint yesterday (albeit Wilkos own make but the brilliant white one, not thd very cheap one) and after resanding the whole ceiling and two coats it looking pretty good. There's still one strip where I filled a crack and the filler is still showing through and raised a little but I'll try sanding that bit down again. The rest of the ceiling is fine.