Black mould in upstairs bedroom in corner and along top of external wall Damp can be a major issue in the home. Find answers to questions or post your own here.

[1sttimerenovator]

Hello
Hoping for a bit of help.
We've moved into a 1930s ex council house (cavity walls...unsure if insulated or not) and were warned (by vendors) that the back wall upstairs gets wet from' driving rain' . We moved in and repointed, put guttering up (there wasn't any on the back wall) and used a stormdry cream barrier treatment.
In the last month black mould has appeared along the top of the wall by the ceiling in the back bedroom and the paint is all cracked and peeling off. Its obvious that the previous people had just quickly painted over and not treated the walls.

There are air bricks (plastic) on the outside of the house match up with roughly where the damp and mould is. They are plastered over inside (not sure if this what it should be like or if it's just for the cavity rather than the inside of the house).
The roof looks ok from what we can see.
The sofits and fascias appear ok too.

Any help appreciated!

Many thanks

[welsh brickie]

make sure the insulation in the loft is clear from the edge of the rafters so that air can ventilate, that could be the cause of the problem,

[1sttimerenovator]

Excellent thank you! We'll check it out : )

[htg engineer]

Probably caused by condensation, open up the air vents to allow circulation of fresh air.