Cost of a single-family house with a granny flat approximately 200 square meters

For timber frame construction, I would even calculate 2300/sqm

And in By or BW currently rather 2500:(

And the basement price can also be adjusted significantly. Our offers for a WU basement 9x12m (most companies no longer build anything else) were all between 70-90K without earthworks. Earthworks then at 25-35K.

And the basement price can also be clearly adjusted. Our offers for a WU basement 9x12m (most companies don’t build anything else anymore) were all between 70-90K excluding earthworks. Earthworks then at 25-35K.

Finished as a habitable basement or purely utility cellar?

Utility basement with 2.56m raw construction height without interior finishing. Included are a concrete staircase without railing/coverings, 4 windows with light wells, 4 interior doors, and 4 empty electrical boxes per room (optionally socket, switch, or light outlet).

Several companies checked, all were within the range.

For that, the double garage can easily be cheaper, 20-25K plus foundation should be sufficient.

At Viebrockhaus, I was told that a usable basement costs 1000€/m2 (finished basement).