Floor plan - plot for a single-family house, slight slope approx. 175m²

I would build a split-level. But probably not with Bien-Zenker. I would be curious to hear what they say about it. They probably want an extra million right away.

The biggest problem I see right now is that the OP has already signed.

Avoidably foolish, yes. But "biggest problem" would be unnecessarily whined about. The provider is not a bad choice.

I would build a split level. But probably not with Bien-Zenker. I would be interested in what they say about it.

Not building a split level here is also not a big deal. And yes, Bien-Zenker would not be my favorite for that either. So much so that I would not even ask them about it. My preferred strategy would be to look for a more suitable base model.

Not building a split level here is not a big deal either.

Honestly, I find it quite a pity here. The plot is so small that it is difficult to stuff everything full of retaining walls and terrain supports. There is not much room for a gently sloping compensation area or something similar. There simply isn't enough space for that. So basically, the only option left is the outside staircase with entrance landing and basement. But the OP doesn't want that. Maybe he would rather do without the terrace and dig in on the south side without terrace doors? But I also can't imagine that. Digging everything out again - that brings us back to the space problem and is insanely expensive. What did you have in mind?

And yes, Bien-Zenker would not be my favorite for that either. To the extent that I wouldn't even ask them about it. My preferred strategy would be to look for a more suitable basic model.

What do you mean by suitable? If the plot were flat as a pancake, the OP would have no problem. Then I can find you dozens of models from the catalogs right away. Or has Bien-Zenker recently also had hillside solutions in store?

What did you have in mind? What do you mean by suitable? If the plot were flat as a pancake, the OP wouldn't have a problem. Then I would immediately find you dozens of models from the catalogs. Or does Bien-Zenker recently also have hillside solutions ready?

I know hillside solutions (except very occasionally and even then mostly as an alibi) from no catalogs, nor exactly as the domain of timber frame panel builders. What I have in mind as "suitable" is simply a basic model in the right width, because an extension is a smaller operation.

I also see the problem with Dietmar's solution that the ground floor is constructed in such a way that you would basically have to excavate and support almost the entire half of the property as a light well. However, I also see that three floors are financially tight. Therefore, the thought again: If you run the ground floor with the railing, basically as a basement, then the cold storage/utility room to the west, because it has no windows, would have to be replaced by a guest/office room with lighting through a light well. To the north, there are windows on the east, north, and west sides, of whatever size, which must then be reserved for living rooms. On the upper floor, then a common room, etc. Then a converted attic. So everything has shifted down one floor. What does Bien-Zenker propose?

What I mean by "appropriate" is simply a basic model of suitable width, because an extension is a smaller operation.

You mean you place the cabin perpendicular to the slope and make it so narrow that the incline within the building envelope is as small as possible? I'm afraid it still won't work without stairs to the front door.

So everything has slipped one floor down.

The problem is the slope of half a story within the building envelope. No matter what you sink or raise, the OP’s dream of avoiding stairs will, in my opinion, be difficult to impossible.