Development plan - Is it possible to enlarge the living area?

Underfloor heating is available.

I really like your version, it will be passed on as is, thank you.
What does KW mean?

With underfloor heating, the architect's proposal is quite complex. You can't just put walls on the screed.

KW = stroller. It can also go to the garage when visitors come. ;)

I am still not clear how the exit to the basement from the terrace is supposed to be remodeled? Is it separated from the terrace by a wall or railing? Do you still need it?

With underfloor heating, the architect's proposal is quite complex. You can't build walls on top of the screed.

KW = stroller. It can also be placed in the garage when there are visitors.

It's not clear to me how the access to the basement from the terrace is supposed to be rebuilt? Is it separated from the terrace by a wall or balustrade? Do you even still need it?

Oh, yes, in an emergency it can also go into the garage. After all, we have now planned a passage there, no idea how one could plan without a direct garage <> house connection – pretty stupid, always having to walk outside in the rain when the garage is practically integrated into the house anyway.
Regarding underfloor heating: Sorry, that was ambiguous. Underfloor heating means there will be underfloor heating in the future. Not yet now.

Terrace: At the moment there is an ugly, massive concrete balustrade. That will go and be replaced with something more elegant; my wife wanted, for example, ceiling-high wooden slats, no idea what you call that. The access there is somewhat awkwardly positioned for me, but the previous owner used to bring motorcycles down from the garage to the basement for repairs – there is also half stairs, half ramp, plus a winch on the ceiling :-/
I would have preferred the stairs somewhere in the garden / e.g. near the utility room, but that's just how it is.

What the woman likes will of course be implemented. ;) I can also well imagine the wooden partition on the terrace.

For me, the passage to the garage has led to the development costs increasing by 50 m2 with the calculation basis.

Please plan a fire door there. But the architect surely knows that.

Development costs are fortunately not an issue for us. Yes, the fire protection door is set.

So, I'll try to upload the current plan status. I hope you can make out something - the documents are so large that scaling them down probably makes the labeling unreadable. Really unfortunate that linking to, for example, Dropbox is not allowed here.

UG: Floor plan unchanged, except for the light well in my future office (south-west), which will be a bit larger and more daylight will come in through a mirrored shaft. Fitness room, a storage room, a technical room (including pool technology), an electrical room (KNX system + network technology need space, plus the house connections will be located there. Not ideal, I originally wanted a small bathroom there, but relocating the connections would be much too expensive and the technical room is already too small for everything)

EG: Dining and living room now combined, access to the kitchen newly through the living room, making space for a wardrobe; for which the small shower downstairs has to give way. More window area, window seat, passage to the garage (which so far was only accessible from outside??), door from the utility room to the (herb) garden. Sliding glass roof as an extension in front of the outdoor seating area (only on top, open on the sides)

OG: Attic is converted into dressing and bathroom, air space over the terrace will have a floor inserted, that will be our bedroom. Parental area thus separated from the rest of the upper floor. Intermediate ceiling will be removed, so ceiling height almost 5m, view of wooden beams. Children's room 1 (east) definitely has the better view, but children’s room 2 has a better layout and the larger dormer (maximum size specified by the development plan). Both children's rooms have stairs leading to the galleries. In the northeast the guest/sewing/reading room, so we can also have some of the view there - the view towards the east is unobstructed over the fields to the Isar meadows. Attic/galleries: We adults will have the whole house for ourselves anyway, so the children should get as much space as possible. Children’s room 2 has the larger gallery as the room is otherwise somewhat disadvantaged. Light height above the stairs everywhere >1.9m.

Exterior views: The lowest row of PV modules will probably be omitted on the north side for better aesthetics. Dormers made of copper. Facade concrete look, red roof, wood cladding at entrance and flush large garage door. Cladding of the window seat made of corten steel.