Floor plan of a single-family house approximately 150-160 sqm on a 480 sqm plot in Middle Franconia

Above all, so that they fit on an A4 sheet ;-) That’s why both floor plans also have a north arrow

You’re right, when it comes to the biggest investment of your life, it’s absolutely sensible to save on proper planning / planning tools :rolleyes:

P.S.: You could also simply rotate the scan by 90 degrees before uploading it here to align it north. Just as an abstract idea...

More important at first were the dimensions...

The floor plans also both have a north arrow

Jokester. In the title block of the drawing, it says the draftsman is named "->Z". That's almost like brain training to imagine that as a north arrow. Man, man, man - really, eh ... no, right?

Can you provide the exterior dimensions, the floor heights, and the wall thickness of the exterior wall?

In my opinion 12.5m * 8.5m Exterior wall 50cm?? Without a basement, the house connection room is definitely missing.

OK the OP has probably drawn that a bit too optimistically. The linked building has external dimensions of 12m*8m according to the description. For a wooden house, I would not estimate wall thickness as 50 cm.

do you have an offer from them?