Mould - condensation versus leaking gutter?

[lora]

Due to one of the coldest winters in my memory, for the first time in years I've wimped out and kept the bedroom window shut for the last couple of months.

Used to leave it open all the time whatever the weather. After the recent snowfalls and subsequent thaws I've noticed damp on the bedroom wall, rapidly becoming mould, just underneath one of the guttering joints. Now starting to spread over the wall towards the window. What should I be looking for to tell if it's the gutter that's leaking or lack of ventilation that's caused it? It's a Victorian stone terraced with (as far as I can tell) either stone or concrete guttering that has lead joints.

 

[Burnerman]

I think a lot of us have experienced problems this winter, things we haven't seen before...this has been due to the huge quantities of ice that have built up, preventing the gutters from flowing. I've actually seen a house recently that had melt water entering the soffit space, and running down the inside of the window frame. Your problem may not reoccur, but its worth having the guttering looked at in case any joint has been disturbed.
John