No picture attached, ( you must wait for a picture to clarify, before you submit ) do not use meters, this is the USA, and sq feet are meaningless.

Use a floor plan uploaded as a jpeg, with every foot and inch of everything noted. Add to a comment box below

https://www.houzz.com/discussions/6411000/how-to-houzz-how-to-ask-questions-how-to-get-helpful-answers-and-e#28784466

Sorry, I had technical issues with the entire post (first two rounds of project description and picture disappeared, then showed up but apparently didn't go through. Hopefully it is there for good now). "This is the USA"--no, this is the internet, and there might be people who are less US-centric in their approach to this platform. (And by the way, you tell me "sq feet are meaningless"--???) I am not asking for an exact floor plan, just general advice on where things should be. The link you added to your post suggests being nice to people who are newish to this platform. Maybe take that to heart next time you respond instead of berating me for posting "meaningless" information using the metric system?

Since redoing for your parents use, are you planning with accesibility in mind so parents can “age in place”? Now would be the perfect time and would make some differences in the design.

Yes, exactly. The actual "sleeping quarters" are upstairs, but in case one of them can no longer navigate stairs, we are thinking about an "old age" bedroom with a bathroom right next door, also to make a possible managed care situation easier.

Having done a renovation for precisely aging in place some things to think about. A bathtub is a dangerous thing especially with those lovely deep European tubs. Curbless shower the gold standard but just a few inches curb can be navigated very well. Unless wheelchair is anticipated. A free standing stool/bench instead of a built in seat can be maneuvered to where want it and allow flexibility if there needs to be an aide helping with the shower. A sliding bar with handheld shower wand is a good do everything fixture. Grab bar horizontally along the back does double duty as a towel or facecloth bar. Another one vertical at entrance is very nice to have when entering and leaving over the small step. A high toilet is best. If not already have a washer/dryer on the first floor try your best to plan for one.

Thanks for these thoughts! We do not want to add a bathtub (see description of the project above), my problem right now is less the details for age-appropriate aides but more the placement of the sink, the toilet, the shower in a space with two doors and a window facing a street. But I will definitely add your suggestions to our list of things to specify once we start purchasing the individual components of this bathroom.