Stud wall - dampness?

[bananaskin123]

We have a stud wall between the hall and downstairs loo/shower room. We had a small bookcase in the shower room (its quite large) full of books and a few months ago I notice "bubbles" in the shower room wall and the hall. removed all the books and took the book shelf well away from the wall. Decorator rubbed it down and put some anti damp paint on it. This was around about October. However this is showing some bubbles again, not near the skirting particularly but half way up the wall in a straight line going across. We suppose there must be some dampness somewhere. Not noticed anything on the wooden floor. Only thing I can think of is that the guttering on that side was overflowing for some time before it was cleaned late summer. Its a mystery and I probably have not explained at all well but any advice would be appreciated.

Sorry, I’m a bit confused. If it’s a stud wall between the hall and shower room -so internal wall-how is the guttering affecting it?
Are you sure there isn’t an underfloor heating /water pipe in that area that has corroded and slowly leaking causing damp?

Theres a leak detector guy on TikTok who is amazing and the damage that can be caused by a, seemingly small, leak is incredible.

I have a similar problem but a case of keep area well ventilated.

Musty smell as well 🙀

Root cause of problem sorted out, now just waiting for stud wall to dy out and it will take ages 😔

When we run the shower, I can see damp patches forming on the opposite wall near the window, where the wall is coldest. It's just condensation and I was surprised at how much forms very quickly. Definitely check for gutter/pipe problems but it may just be condensation. After a shower, I now always open window and leave extractor fan on until I can see the damp patch disappear.