Floor plan city villa with hipped roof approx. 170 sqm

I can't quite imagine the look with the carport on the extension in conjunction with the roof on the extension yet.

That is actually a sticking point. Maybe a flat roof could be extended over both? Unfortunately, I can only suggest that - my program fails as soon as it comes to aesthetics.

Here is an example for the upper floor. However, the children's rooms here are only 13.5. With some fine tuning, you might still get 14m² for both.

Here is another upper floor with more children's rooms and fewer bathrooms.
The ground floor remains the same.

Thank you very much for the visualizations! I really like how you always put thought into it and I also greatly appreciate your designs.

According to the development plan, a roof pitch of 15 degrees is prescribed. There are exceptions (garages, etc.), but the annex does not fall under these. For this reason, I am not sure if a flat roof over the carport and annex would be permissible.

The "new" ground floor doesn’t quite resonate with me yet. I basically liked all the rooms in their geometry and dimensions on the previous ground floor. Wide hallway (no tunnel feeling), sufficient (although rather unusual) wardrobe, rectangular, narrow utility room, almost square office, nice distance between TV and couch in the living room, which itself is “niche-like” in the annex, kitchen not too large but furnishable, sightline from the front door through the double door to the garden... The only thing I don’t like so much is the staircase in the utility area, but it would be manageable.
I can understand your arguments for mirroring it, but especially the combination of carport & annex as well as, for example, the new utility room in its form still don’t appeal to me. Your upper floors are nicely straightforward, which I like, even though I would miss the open space a bit, as it gives the rather small and “practical” upper floor a bit of “spice.” But in the end, the open space would be forgivable.

Maybe you have a completely different idea that doesn’t even rely on the floor plan I posted... or how would you divide the house including the carport if you approached it from scratch? Under the premise that we must have an upper floor which is only 2/3 the size of the ground floor. I would be extremely interested in that. Maybe that would be a new starting point that I could take up for further planning.

Oh really! I find the new ground floor more appealing. The open space is back in the upper floors - I thought that was visible.

I can hardly imagine pulling something out of your pocket that you like. In my opinion, your priorities are still somewhat outside of what I can understand. For example, square rooms are only nice for dancing. For furnishing and decorating, they are completely unsuitable. Especially a utility room needs as long walls as possible for installation. But beds, wardrobes, and sinks also usually want to go somewhere against the wall. That’s why it’s best to plan rectangular rooms.

Looking from the front door all the way into the garden is rather disadvantageous for terrace coziness when the mail carrier rings. But okay.

If I feel like it, I’d be happy to doodle a bit more. But I already think the last draft with the changes is pretty good.

We have a roof pitch of 15 degrees specified according to the development plan. There are exceptions (garages, etc.), but the extension does not fall under this. For this reason, I do not know exactly whether a flat roof over the carport and extension would be permitted.

At least in the case of a carport extending into the extension, I suspect there is no exception here in case of doubt.

On the premise that we must have an upper floor that only makes up 2/3 of the ground floor area.

That means conversely: ground floor = 3/2 of the upper floor = 3/5 of the whole => at least 20% must first be removed from the total area before it can be "evenly" divided. My approach would therefore be to look for correspondingly significant rooms in the room program that are designated by lot to have to go downstairs. This means that until this measure is met, for example, utility room, office, guest room are probably downstairs; ground floor terrace areas are more likely to be covered further and upper floor terrace areas are practically dead from the outset. You can also trick the roof: just as, for example, dormers of the size of the entire bathroom are often built on gable roofs, one can conversely partially lower areas under slopes below the 230 cm mark.

...EG terrace areas are more likely to be roofed over in case of doubt ...

Is it sufficient if I roof terraces to include them as full square meters in the calculation? How is this defined?