Is it 'damp' on old plasterboard?

[rich3422]

Hi,

I am renovating a 50 year old ex council house. I have removed wallpaper from the front upstairs bedroom and on the plaster under the window on the wall to the outside of the house, there are some black spottles. If I intend to paint the plaster in the room, do I need to paint this first with some special paint?

Many thanks,
Rich

 

[joe-90]

It sounds like mould due to condensation. Apply some Polycell 3 in 1 mould killer.