Cost estimate single-family house ~175m^2, 3-story

Thank you very much for the information, exactly for this reason I opened the thread, because as a layman I of course do not consider all points by far, you are of course right.

I have also (second-hand) heard of similar negotiated specialist dealer prices. Industrial parquet is apparently really cheap (although 15-20mm solid wood parquet, and we really like the look, we would also choose industrial parquet if it cost twice as much). I have already calculated about 5-10% waste, do you think that is too little? What is of course missing is the material besides parquet. Adhesive, impact sound insulation (do I need that under the parquet? I thought it is glued over the entire surface to the screed?) etc. I simply added this to the installation cost. What do you think this item would amount to? In this case, have I underestimated the installation cost?

Regarding the stairs: the stairs are included in the offer, it is only about the "covering" of the stairs (is that what it’s called?). What do you think that will cost in terms of labor/additional material?

Basement stairs (rough, should remain like that for now) are already included in the basement price.

Do you already have a floor plan? With 3 floors and 150-160 sqm of living space, you lose a lot of area to walls and circulation space. The high ceiling heights also make the staircase look very bulky.

No, there is not yet a precise floor plan. We are aware that we lose quite a bit of space for movement areas. We do not want a separate staircase, not least for this reason, but rather to integrate the (open) staircase, for example, into the living area.