I have a damp area in my loft which is developing black mold. This section of the wall was re-rendered on the outside a year ago as it was obviously letting water in. I didnt remove the damp plaster on the inside at the time and just reskimmed over this. Should i have removed this plaster? do you think the damp coming though again is trapped moisture? if it is i will take down this section of plaster work and let it breath for a bit. any idea how long i need to let it do this? cant think of any other reason why the wall would be wet. the rendering was done spot on and so i know this will not be leaking.