Floor plan single-family house approx. 160 sqm - suggestions for improvement?

But you don't install a highlight if the rooms below have to suffer.

You are basically right. But if we couldn't subtract the gallery, the floor area ratio would be even higher. At the moment we are at 157 sqm (according to the calculation method valid at the time). Without the open space, it would be 161 sqm.
Do you understand what I mean?
It is definitely a tricky task, but that's why I'm here

You can build a gable roof house with an eaves height of 4.50 and a KS of about 120-140 with a gable roof that does not reach two stories. A floor area ratio of 0.3 allows for a house with a total of 150 sqm. As far as I know, this includes all rooms inside the house, including technical rooms and storage rooms. The calculation of living space is different; storage rooms are not counted there. But as far as I know, these are two different things. Can you clarify this before speculation is made based on false assumptions?

If the ground floor has a room height of 2.6m, and you subtract the suspended ceiling (0.5m?), that results in a knee wall height of 1.4m, right?

If you want a room height of 260 cm, then the story height will be about 290 to just under 300 cm. I found this picture:

125 cm far right, with a story height of 285 cm and top edge of finished floor 40 cm above the 0-height reference point.

I can’t be more specific now, but you just have to take it into account. That’s why the 2m line also belongs there.

And, of course, considerations about which windows.

With an eaves height of 4.50, you can have a gable roof house with a KS of about 120-140 with a gable roof that does not reach two stories. A floor area ratio of 0.3 allows a house with a total of 150 sqm. As far as I know, this includes all rooms within the house, including technical rooms and storage rooms.

Yes, according to the current land use ordinance, that is correct. However, §20 (2) of the 1977 land use ordinance applies. It states: (2) The floor area is to be determined by the external dimensions of the buildings in all full stories. The areas of living rooms on other floors, including the stairwells belonging to them and their enclosing walls, are to be included.

And since bathrooms and storage rooms are not living rooms according to the state building code, they must be deducted accordingly. This also corresponds to the statement from the building authority. Otherwise, we would probably be well above 150 sqm... The regulation with "less than Xy room height" does not apply either. Here, the external dimensions of the ground floor (1 full floor) plus rooms above actually count. Or in other words: external ground floor dimensions * 2 minus bathroom, upper storage room, and air space. Quite complicated and completely different since 1990.

I just googled to find a good example - especially regarding the windows for illustration. The exhibition house of Weberhaus in Wenden is roughly what we would like to aim for. However, without a balcony. The gallery window would then go into the gable. And of course smaller.

Yes, then go ahead and draw your roof ... the Weberhaus has no skylights, has the bay window, etc. Your children's rooms are all illuminated by skylights. And then you have to see how high the kneewall will be. Otherwise, you will also need kneewall skylights so that the children can actually look outside at all, at least as long as they are under 150 cm tall.