Hello
I'm completely new to this, but I think I could get a lot of good tips from the rest of you here on the forum.
The thing is that my girlfriend and I live in an old wooden house with a brick foundation... I would assume the house is from the 1920s or so.
We have a small bathroom upstairs but only with a shower and no possibility for a bathtub

and there's certainly something special about lying in a warm bath with a good book

Well, then I got the idea, why not turn the old pantry into a relaxation room with a bathtub... not a proper bathroom but just a quiet room with a bathtub to relax in sometimes.
The room isn't very big, about 3.60 * 1.65 m, but that's enough for this...
The walls are plastered and there's a concrete floor.
I was thinking of bringing water to the bathtub from an existing modern plumbing system to the bathroom one floor up since it's easy to access, and the drainage will be solved by running the drainpipe from the tub through the wall to the existing floor drain.
After reading other posts, I think the most appropriate thing would be to half-tile the walls and then paint the upper part with appropriate breathable paint.
But when it comes to the floor, I'm unsure, what is best, wooden decking or tiles? Or is it just a matter of taste?
I probably shouldn't need to install any moisture barrier since I won't have any water other than in the bathtub. Sure, a little might spill over, but not in quantities like in a shower.
I'm also thinking about ventilation, since there's already a pipe out from the room, I thought of installing a small bathroom fan to bring in fresh or expel humid air, could that work?
Thankful for all help and tips