My victorian terrace is bigger than the one next to it, so exposes a single brick thick wall to the western weather (ie. it's the width of a brick thick rather than the length) I currently let it out, and it's all been fine for 5 years till last winter's wet weather. I went there last week to find half the wall covered in black mould (the current tenant is not fussy!) . The mould is pretty much aligned with where the wall is exposed. The outside of the wall is rendered, so it may be condensation build up rather than rain soaking in (the window sill was also very mouldy), so I'm hoping a good clean, a coat of paint, and instructions to the tenant to keep the room aired will sort it. Any opinions, or recommendations on paint? Thanks for any suggestions.