2 residential units on 185 sqm of land?!

The regulations must be adhered to, whether they sometimes make more or less sense.

Let me reformulate the original question at hand to conduct a meaningful discussion and receive answers.

1. How many square meters would you plan for a 2-room apartment or a 3-room apartment of living space?
2. How many square meters would you allocate for the staircase in a multi-family house with 6 units, two per floor?
3. How many additional square meters would you calculate for walls, balconies, and other areas that "consume space" and cannot be counted as living space?
4. Result: How much floor area would you set for the multi-family house with the 6 units to realize this?

(185 sqm are currently available as building area. The question was whether the project can be realized with this. There is the possibility of acquiring land from the neighbor, so one could calculate with 185 sqm +6 sqm; +12 sqm; +18 sqm)

I must say that I am aware that the question cannot be answered universally and depends on many factors; nevertheless, I would be pleased about many constructive answers. I hope there are people with experience who have already implemented similar projects and can provide a "rough" estimate.

Honestly, the topic is so specific, go to an architect whom you will need anyway and get advice.

I agree. You have now received a few examples. You simply won't be able to generalize. It will remain within the scope of the examples.

That is possible, even very well; but it requires a creative mind. A forum – not even a Kerstin or Yvonne – can accomplish this.

So take money in hand and find an architect you trust and work on the project with her/him.

I could now list many requirements for building a multi-family house – some quite expensive must-haves. In my opinion, it is better if this is explained in direct exchange with a real person.

Construction expert on the go