Damp Walls in my living room and next doors kitchen after a leak

you will need to strip it back removing all the plaster back to the brick allow the wall to dry out properly this could take a few months, before re plastering good luck alex

This sounds like a recipe for disaster!! Black mould is pure damp and the spores are dangerous to your respiratory system ,water damage & fungus will continue to get worse overtime if not treated properly the key is removal and replacement of said plasterboard& any timbers in contact with this is essentially the Anwser it needs to be allowed to dry out properly or it can easily turn into wet rot or this can turn into dry rot depending on the humidity dry rot being the more severe of the two can take over your whole house growing through walls under plaster both are bad news and should not be ignoredunder any circumstances both cause massive amounts of damage and very costly to deal with Basically there waterleak their or the landlords responsibility to repair contact your local council for further advice