Wet / Damp Patch immediately outside bathroom door

girl_withno_name

Wondering if anyone has any ideas to possible cause of a wet / Damp Patch just outside my bathroom door. Upstairs bathroom.

On the other side is a bath with shower over with hinged glass shower screen

I don't personally use this bathroom, so difficult to say what's happening. But my lodgers haven't noticed any patten to when it occurs

Noticed a couple of times previously (months ago) but more often recently. The black marks are damp mould coming through from the underlay.

No sign of leak from the ceiling above, or it coming through into the kitchen below.

https://imgur.com/a/3fAULk4

Aylesbury_Duck

A leaky seal around the bath, perhaps? My guess would be water making its way between the bath and wall. A very small leak might mean the problem not being a timely fit to the use of the shower, it might take some time for the water to leak through, dribble down the wall, collect on the floor and sleep along to the doorway.

MovingForwards

Could also be your shower screen isn't stopping the water from exiting the bath when the shower is used.

Have you asked your lodgers to put a bath mat / large towel down on the floor to see if it is the screen?