Retrofit bathtub or shower?

Hello Since we only have one bathroom, there are often backups! we have a guest WC without a shower / tub. Would it even be possible to place a shower or tub in front of the wall? Underfloor heating is installed, which would probably make "drilling downwards" difficult! I am grateful for any suggestions. It's always better to have already heard other opinions. Thank you and best regards

I hope you can see it, in front of the guest WC there is a wall with a mirror - in the corner there would be space for a bathtub/shower. It would then be in the wardrobe at the same time, so I am open to ideas

A floor plan image would be helpful. That way it is really hard to recognize. At least for me.

Unfortunately, we do not have it. I built the wall into the room myself back then.

I also don’t understand right now where you want to place the shower/bathtub

It’s then at the same time in the wardrobe, so I’m open to ideas

That confuses me especially right now?

Unfortunately we don’t have that. I built the wall into the room myself back then.

Maybe at least a hand sketch of the room/the anteroom (wardrobe?). Or a floor plan before the wall was built and then just add it in? Ideally probably with measurements and even more ideally probably a floor plan of the entire floor?

A floor plan image would be helpful. It's really hard to tell that way. At least for me.

Unfortunately, we don't have one. I built the wall into the room myself back then.

You will have to make a sketch whether you want to or not. And it needs to be to scale if you are serious about an upgrade/renovation. Unfortunately, I can't see any dimensions of the room either – how could I, if you don't show all four corners and walls or a sink and a toilet. I don't see a coat rack.