Floor plan draft for a 220m² single-family house

The explanation is very simple: he does not have these concerns himself yet. How should he?

My impression is not that they are planning and building their first house. "How should he?" sounds a bit as if a complete outsider to the industry were planning and executing here. Or not?

When I look at the whole flood of contributions, I cannot imagine that this process is being accompanied in parallel by an architect according to the planning structure based on the HOAI. A building design cannot be generated through forum posts.

It is completely sufficient for the service phases 1+2 (basic evaluation + preliminary design), which seem to be the focus so far, if the architect's proposals, the client's / client's wife's ideas, and the contributions of some accompanying specialist engineers (soil surveyor, surveyor, structural engineer) are coordinated and combined into a building concept. This does not seem to be the case here.

Yes, we have concluded an architect contract according to HOAI with the service phases 1-4.

That would be unbuildable. Wouldn't all houses with setbacks on the upper floor and, for example, roof terraces be affected? Am I understanding that correctly?

No more stepped floors at all? So only congruent floors from now on?

No, stepped floors are not a problem. Even the laundry-drying roof terrace is possible. The problem here is that almost the entire approximately 45 m exterior wall length of the upper floor stands literally "beside" the ground floor wall, except for about 75 cm. The structural dimension is already really strained, and the thermal dimension then completely spoils the plan.

My impression is not that they are planning and building their first house.

They rather give me the impression of being experienced – with solid basic homes, perhaps occasionally a building with normal stepped floors in between. But no one has probably ever built a house so consistently packed with critical points.

Sounds a bit like a complete industry outsider is planning and executing this.

"Industry outsider" is actually a not so rare accurate term for today’s young architects.

What I would personally be interested in: What does Architect 1 say about the fact that his masterpiece is not buildable at all? I mean, does he get paid for a design that is not feasible?

What I would personally be interested in: What does Architect 1 say about the fact that his masterpiece is not feasible to build at all? I mean, does he get paid for a design that is not realizable?

No idea. I have no contract with him. What he arranged with the builder - no idea.