Floor plan of a semi-detached house with a guest room

I don't know any good reason why a semi-detached house should only have half the costs. Especially if both halves are built independently. At this point, it is also not clear to me where the 230 sqm should come from; roughly estimated, I don't come close to that.

I don't want to go into all the details of the floor plan; others can do that better, but where are the grandparents supposed to sleep during the 4 months if grandpa is no longer very mobile? Hopefully not upstairs?

For assessment, it would also be helpful if you roughly mark where paths are supposed to run, where parking will be, and where a possible garden shed will go.

What is the distance from the building envelope to the street? Are pure parking spaces allowed outside the building envelope on the street side, or must they also be within the building envelope?
With KFW 40, the exterior wall may be slightly thicker. Is anything already known about the thickness?

Just make one big calculation: 3,000 € / sqm. That’s 160 sqm = 480,000 € Additional construction costs: 50,000 € Garage: 25,000 € Outdoor facilities: xxx Then you’re at 555,000 € + outdoor facilities + land. If you can live with that number, you can keep planning :cool:

building window to the street 3m
Exterior wall 36.5 was specified
Parking spaces are allowed in front of the house on the street, the west side is designated as green space

Stupid question: why 3000? I want to understand. We'll leave out the garage for now (you can get a prefabricated garage for 10-15 there too); for the outdoor facilities, we initially planned 15 for the essentials (paving, terrace), we estimated higher for ancillary building costs. So I'm really grateful for your advice; if we are completely out of budget, we wouldn't buy the plot (we still have about a month to decide). It would definitely be a shame, but better than refinancing and getting completely into debt