Any advice on best way of treating green and white fuzzy mold on wall in corner of bedroom? We moved in 8 months ago and two months ago found it was wet at the top of the chimney breast in that room (chimney itself has been removed a few years ago). Now found green and white fuzzy mold in bottom corner of external walls behind sons bed. None of this picked up in Survey and room had been recently decorated so all looked fine….any advice?