Enlarge and fully renovate a single-family house or demolish and rebuild?

Attached in better quality. We’re not making airspace anymore!

Great, now just the section, and then the ceiling plans :)

Great, now the section, and then the ceiling plans :)

Attached is the section. There are no ceiling plans :D

Attached is the cut.

Fine, but it is still Sunday and I want to go hiking.

There are no ceiling plans

There should be some in the building files. Knowing the ceiling panels is very informative.

Fine, but it is still Sunday and I want to go hiking. There should be some in the building file. Knowing the ceiling panels is very insightful.

I really have nothing left. Dug up everything possible ;) I wish you lots and lots of fun and Merry Christmas!!!

I really have nothing left. Dug up everything that I could

I didn't mean the construction file in the sense of grandpa's folder for house construction, but the box in the town hall archive containing the building permit documents from back then. We can also discuss here provisionally without it, but then it becomes quite speculative, and the structural engineer doesn't work with a crystal ball either ...

I basically see good chances, however the floor plans would all three

But how do you see it with the walls of the ground floor, which are all supposed to be removed? I would immediately fear that they support the ceiling elements (hence probably your question about the ceiling panels) or that the walls have bracing functions, even if they are not load-bearing.