How to cure mould like marks on ceiling

[Venture321]

Someone got mould like brownish marks all over the ceiling. This started after they had covered windows for months. after removing the covering it's not got any worse or better. See picture -disregard the wet patch from previous rain ingress

If the room has dried then clean and paint.

@outside1inside The room is totally dry-would you recommend to clean first or just paint over

Have a look at the Zinsser range before you paint. The stain marks would probably come through if you just painted with emulsion over them.

Yep definitely zinser. I use zinser bin and it covers any marks/ dried out wet patches.

This! You won't be able to paint over those stains with just emulsion.

There are lot of stain blocking paints around. Zinssers is a very good make. Just to be on the safe side, I'd paint over the marks with a stain blocker then go ahead and paint as normal. For the place where you have previous water ingress, there is also damp seal paint, which stops any residual moisture in the wall bleeding through. Have a look at the Screwfix site.