Floor planning with a narrowing plot

Hello everyone,
I have here a draft of our potential floor plan.

Development plan/restrictions
Size of the plot => 460 sqm
Slope => no
Building window, building line and boundary => see attachment
Roof shape => gable roof
Maximum heights/limits => TH 5.5m


Requirements of the builders
Room

Area (m²)

Living room and dining area
45

Bedroom
16

Kitchen
12

Office
12

Children’s room 1 on upper floor
14

Children’s room 2 on upper floor
14

Bathroom with tub and shower on upper floor
12

Barrier-free guest WC with shower on ground floor
5

Storage room on ground floor
Min. 3

Basement / laundry room
20

Workshop corner in basement
6

Additionally:
Double garage
6*9m

Wishlist:

[*
Approximate room sizes see table
[*]No gallery or “dead” corners
[*]Please no flat roof projections
[*]No flat roof => gable roof
[*]No additional balconies
[*]Connected living and dining area with large open kitchen
[*]One recreational room in basement as party and sports room
[*]Direct access from garage to the house possibly via storage room or covered access over outdoor paths
[*]Burglary protection on ground floor and accessible areas
[*]Photovoltaics with energy storage and optional emergency power function
[*]Air heat pump?
[*]KFW 55 would be desirable
[*]Large floor-to-ceiling glass fronts in living and dining area - to be opened by sliding function
[*]Floor-to-ceiling windows in the children’s rooms and bedrooms
[*]Exterior blinds in living and dining area and kitchen
[*]All shutters and blinds are electric
[*]Terrace with awning
[*]Water-permeable paving stones for garage driveway => see text part development plan
[*]Green roof on garage => see text part development plan
[*]Retaining wall at the property boundary in the northeast
[*]If possible: sports/hobby room with “normal” windows, no light well, facing bike/pedestrian path
[*]Garage driveway should be on ground level
[*]Partial home automation with KNX, programming and server are done by ourselves
[*]Absorbing acoustic ceiling in living and dining area
[*]Optional:
[LIST]
[*]Guest room on upper floor

House design
Who made the plan:
-Do-it-Yourself
What do you especially like? => The connected living and dining area. The priority is on the living room which ideally should be 5x5m to have enough space for the 5.1 system.
What do you not like? => The spacious hallway, which in my opinion takes up too much space. If you make a half-landing staircase where the guest bathroom is located, upstairs you get huge children’s rooms. Somehow I am stuck there and can’t think of anything better.
Personal price limit for the house, including equipment: 500,000 euros

If you have to give up something, which details/extensions
-can you give up: Some garage length.
-can’t you give up: Large living room, large open kitchen. Lots of light in the house

Why did the draft turn out as it is now?
Orientation of the terrace to the southwest, building window

Can you first state the floor area ratio and the plot ratio?

Number of full storeys is 2
Floor area ratio is 0.4

One more addendum. The house footprint is 116 sqm in this plan, garage and paving are 117 sqm.

According to the excerpt from Ordinance on the Structural Use of Plots of Land (Baunutzungsverordnung - Land Use Ordinance): (4) When determining the floor area, the floor areas of 1. garages and parking spaces with their driveways, 2. ancillary facilities within the meaning of § 14, 3. structural installations below the ground surface, through which the building plot is merely underbuilt, must be included. The permissible floor area may be exceeded by the floor areas of the installations referred to in sentence 1 by up to 50 percent, but not more than a floor area ratio of 0.8; further exceedances to a minor extent may be allowed. So it should be fine. 460 * 0.4 * 1.5 = 276 sqm compared to 233 sqm planned area without terrace and garden shed

Unfortunately, it is not possible to determine exactly what kind of staircase this is supposed to be and how it is designed. You mention a landing staircase. Dimensions are also missing to understand whether the staircase fits. And dimensions in the site plan for the building envelope would also be helpful.

And room labels are also missing. Is the large arrow supposed to indicate the north direction?

The terrace exceeds the building envelope. That wouldn't work here. At your place? Please check. Karsten