Hi all. I live in a circa 1903 victorian end of terrace house and last year I stripped the walls of the end room of its wallpaper as there was damp and mould in the bottom corner. I have since treated this area of mould with anti mould paint and it hasn't come back in over a year. However, on the adjoining wall and around where the window is there is a fair amount of discolouration coming through the plaster and I wondered if that too was mould and if so what would be the best way to get rid of it/prevent it coming back? The wall in question is north east facing and the plaster fairly old although couldn't say exactly how old. The exterior wall looks discoloured too but I have cavity walls so it can't be water penetration. Please see the image for clarity. Any suggestions are welcome.
