Weird one

[nicholas221078]

Hi all.
In 1 corner of 1 room which is adjoining to the neighbours, I get mould build up in the corner , it literally starts 1 inch down fron the top.
I have re boarded the ceiling 4 weeks ago and painted, now this.
It did happen hear in the past due to the drain pipe blocking up, the water started splashing and hitting a gap between ours and the neighbours fascias, this was sorted.
I've checked in the loft, pulled all insulation back and it's dry up there on the top , I did manage to squeeze My hand down the brick face in the eves and it felt dry.

What else can it be
Thanks

 

[Wayners]

It's a cold spot so condensation forms on surface.
You can add insulation to the back if you can gain access and run a dehumidifier for a few hours every evening.

Also don't dry washing inside without a dehumidifier and try and find ways to increase ventilation.

Watch the skillbuilder YouTube channel on condensation