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Hi All,

This is on a traditional 3 bed semi detached house

We have a problem with black mould. It is on external soffit boards and builds up around upstairs windows too. In a few places it is internal on what I can best describe as the internal soffit immediately inside the windows.

The black mould on the soffit boards is mainly on a problem on the north side of the house, on the window frames - old aluminium double glazed unit about 15 years old - it tends to be all round the house, but on upstairs windows

Despite what I describe here I don't think we have an inherent structural damp problem, it just that this black mould, once set, seems to spread and I suspect will be difficult t get rid of.

Can anyone help with my options please. Like can I simply rub down and paint the soffit boards, could I PVC clad them or is more drastic action required.

Any advice or pointers to other discussion on this much appreciated.

Regards.
FTF

Mould spores are in the air everywhere all the time!
In dry conditions they do nothing!
In damp conditions they start to grow and will rot wood and cause nasty chest illnesses.
Basically you have a damp problem, probably caused by the way you live.
Firstly, we all breath and sweat, this water vapour about 2.5 litres from each of us per 24 hours looks for the nearest cold surface on which to settle or invade.
Overnight, we sweat about 330 ml of water that invades our beds and makes them feel cold.
The saturated air we breath out, usually condenses onto our windows. If the windows are not the coldest spot in the room, then it will go to where ever the cold spot is.
On top of this we have steam from the bathroom and kitchen.
Water vapour from wet things drying on radiators.
Bathroom and kitchen extractor fans should always be used.
Bathroom and kitchen doors should always be closed.