I have a top floor apartment. On one area of the bedroom wall, below a sloping ceiling, and to the right of a double glazed window, there are water marks. The fan in the ensuite is working and runs for 25 mins after the light is switched off and there is no sign of condensation on the bathroom walls. However in the attic I can see that the extractor fan's ducting behind the sloping ceiling's plasterboard is the "flimsy uninsulated flexible type" rather than the solid plastic ducting used in the attic. There is also water lying in the flexible ducting where it runs horizontal prior to falling down to the ventilation grill in the soffit. What is my best course of action? The apartment is 3 years old.
