Floor plan draft for a 220m² single-family house

Yes, I had already thought about mirroring. But then the living room would be completely in the north. Can that be justified?

Definitely. That was originally the wish during the conversation with the architect (not because of the north but because of the room sequence). But it couldn't be realized because of..... I don't even remember.....

Definitely. That was originally the wish during the conversation with the architect (not because of the north but because of the room sequence). But it couldn’t be realized because of..... I don’t even remember anymore.....

I suspect the architect’s hair on the back of his neck stood up and he didn’t want to be blamed for it later. Well, mirroring is easy. You can always do that – architect or not.

So I was a bit cheeky and mirrored the floor plan. I have to admit, the highway would probably be a big nuisance for me too. I would want to shield the noise as much as possible. In that respect, the mirrored version with the garage on the right as a barrier would be worth considering. And the north side actually becomes the quietest corner in the house. Quiet and dark.
Child 1, however, would have the short end of the stick. But there will probably always be some drawback.

Garage on the right is not possible. The property slopes downward in this area, and a garage could only be built there with significantly increased costs.

What kind of quirk is this with the 6.20m? I mean, how do you come up with that? Is there some sort of acoustic ideal measurement?

I had speculated in that direction too: a resonance frequency that appears in the "defining" chord of the favorite film music or something like that. I couldn't really argue against that – after all, in my youth I also once planned a house whose "core element" was a glass wall to the living area, which turned the garage into a display case for the Camaro.

If such a 6.20m long living room is possible in a 145m² apartment,

... then let's ask the other way round: where are the supporting beams?

Garage on the right doesn’t work. [...] building a garage there would only be possible with significantly higher costs.

It doesn’t have to - it can stay on the left. Garage-pantry passages are, in my opinion, massively overhyped, and daylight in the guest WC is not decisive. However, the reasoning doesn’t quite make sense to me: the slope of the plot remains the same regardless of which part of the building complex you put there (?)