Planning of multi-family house 1200 €/m²

There is slope on the property anyway. How do you balance that out? A partial basement should make sense anyway.

If you ask me, economically it's nonsense like Eulenspiegel. Partial basements can easily have a higher price per square meter than full residential basements. So in terms of production costs, in my opinion that would kill the return, you'd probably be more efficient if you arrange them Swiss-style at the top here.

But if I maximize the above-ground area with living space, it makes sense to build the non-living area downward.

There is a slope on the property anyway. How do you level that out? A partial basement should make sense then anyway.

That amounts to maybe 20-30cm across the entire width of the property. That doesn't bring much benefit.

But if I maximize the above-ground area with living space, it makes sense to build the non-living space downward.

No, as you yourself say:

That amounts to maybe 20-30cm over the entire width of the property. That doesn't bring much -

According to my basement formula, 90% of the basement costs here are luxury. The net additional enclosed space would therefore be a Pyrrhic victory.

Huh? I don't understand what that has to do with the slope. Although the profit margin decreases with the basement, more living space in the attic also means higher rental income?

On another note: according to the [Landesbauordnung], I don't even have to comply with the 2.3m in the attic. It only has to be less than 3/4 of the floor below that is at least 2.3m, right?

Something different: according to the state building code, I don't actually have to comply with the 2.3m in the attic. It only has to be less than 3/4 of the floor below with a height greater or equal to 2.3m, right?

In my opinion, it then becomes a full floor. But you can argue with the setback that the building does not appear as bulky and is lower than with a pitched roof and casts less shadow. I'll ask again. How big is the existing house? Length, width, height?

According to the state building code, I do not have to comply with the 2.3m in the attic. It only has to be less than 3/4 of the floor below greater than or equal to 2.3m, right?

This interpretation is, to my knowledge, correct - as I already noted this morning at 00:40. Presumably, the objection was raised because I had to add some blah blah to fulfill the minimum length "rule" :-(