I purchased a 60 year old house last year and a few months ago I noticed an odd wavy pattern in the paint just above the floor trim. The wood floor was also noticeably darker in that area, so I decided to pull back the quarter round and see what was going on.
This wall is on the outside corner of the house. I have not noticed any dampness/water in the plaster wall or on the floor up to this point. The wood that came off when I pulled back the quarter round is dry, very light and crumbles when I break it apart.
I'm currently planning a bathroom reno, and I'm wondering if this is something that needs to take priority.