Black mould, and condensation in ground floor corner bedroom Damp can be a major issue in the home. Find answers to questions or post your own here.

[Tugaville]

Hi Everyone,
my son's bedroom has black mould, white mould (I think) in the bottom corner, the previous owners covered the wall in some thick lining paper , probably to hide this issue.
I clean it , but it keeps on quickly coming back, also noticed the side wall that I had skimmed , regularly now gets white deposits, aswell and condensation in the corner where 2 walls meet, during winter the room is always above 68% RH.
also on the outside wall of the room, the pointing is very crumbly.
Do you reckon the pointing would cause the condensation and mould in the room? If not any ideas what could be the cause, i open the windows regularly and use a dehumidifier daily, it bring down the RH, but shortly after I turn it on it goes back up
the room has 2, 100mm wall vents, so fresh air comes in the room.
The room has really big window, so I know this doesn't help either.
Thank you in advance for any help given.

[stoneyboy]

Hi tugaville,
Presumably you have solid walls. Suggest you run the dehumidifier 24/7 but not when the windows are open. Try this for a month or so and see if it has any effect.
Regards S