Single-family house - Major renovation - Change of floor plan

I have attached the original plan from 1938, maybe it helps. Only the old building is shown, then 2 rooms were dismantled above in 1957, as well as the single room on the left on the ground floor in 1955.

For such a conversion, more information is needed. Before anyone gets involved, it must first be clarified which walls are load-bearing, preferably by a professional. Then it is best to show the current state with the load-bearing walls in red. Additionally, as an extra file, the target state with new walls in yellow or similar. Important lines, pipes, shafts, or chimneys should be marked. Also, the north arrow belongs on it, and preferably the entire property with access and parking spaces. So simply everything.

I attached the original plan from 1938, maybe it helps.

I thought so. Add the rest too (and don’t forget the views – keep in mind: we have to wrap our heads around your house a bit more laboriously than you).

Is there already an extension in the west? I am interested in the plot, location of the terrace, etc. Maybe also some exterior views in the current state to get an impression. Then the dimensions of the modernization are interesting: is it just supposed to be spruced up with a breakthrough, or are window relocations also included in the budget? Are the load-bearing walls known? Is the planned bathroom already a bathroom? Where are the drains and other pipes located? Are the size specifications in the attic actual sizes or just the floor size? Roof pitch? Knee wall?

With a house width of 6.80m, one will probably have to live with the "tube-like" shape of the rooms. It's the same with me, I have 7m (and a length of 10.5m), and the children's rooms are 2.80m wide, but they share the house length. For my room, I have "treated" myself to 3.30m.

I also think more information is needed about the current state, what must be preserved, how far it is allowed to go (e.g. further extension or similar). And about the budget, just because the architect's estimate is so high doesn't mean that has to be the possible amount.

The upper floor looks strange. Is there currently an enclosed and inaccessible room? What is inside?

The wall in the ground floor bathroom might be non-load-bearing. The rest probably is. A clear case for a structural engineer.