ᐅ Floor Plan Design for a Decreasing Lot Size

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

Development Plan / Restrictions
Plot size => 460 sqm (4950 sq ft)
Slope => no
Building window, building line, and boundary => see attachment
Roof style => gable roof
Maximum heights / limits => ridge height 5.5 m (18 ft)

Client Requirements
Room

Area (m²)

Living 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 bathtub and shower on upper floor
12

Accessible guest toilet 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 x 9 m (20 x 30 ft)

Wish list:

• Room sizes as shown in the table
• No gallery or “dead” corners
• No flat roof overhangs, please
• No flat roof => gable roof only
• No additional balconies
• Open-plan living and dining area with large open kitchen
• One living room in basement as party and sports room
• Direct access from garage to the house, possibly via storage room or covered outdoor path
• Burglary protection on ground floor and climbable areas
• Photovoltaic system with energy storage and optional emergency power function
• Air source heat pump?
• KfW 55 energy standard would be desirable
• Large floor-to-ceiling glass fronts in living and dining area – operable with sliding function
• Floor-to-ceiling windows in children’s rooms and bedrooms
• Exterior blinds in living/dining area and kitchen
• All shutters and blinds are electric
• Terrace with awning
• Permeable paving stones for garage driveway => see development plan text section
• Green roof on garage => see development plan text section
• Retaining wall at northeast property boundary
• If possible: sports/hobby room with “normal” windows, no light well, facing bike and footpath
• Garage driveway should be at ground level
• Partial home automation with KNX; programming and server will be done personally
• Sound-absorbing acoustic ceiling in living/dining area
• Optional:
• Guest room on upper floor

House Design
Who designed it:
- Do-it-Yourself
What do you particularly like? => The connected living and dining area. Priority is given to the living room, which ideally should be 5 x 5 m (16 x 16 ft) to have enough space for a 5.1 sound system.
What do you not like? => The large hallway, which in my opinion takes up too much space. If you put a half-landing staircase where the guest bathroom is, you get huge children’s rooms upstairs. Somehow I’m stuck on this and can’t think of anything better.
Personal price limit for the house, including features: 500,000 euros

If you have to give up something, which details/extensions can you do without: Some garage length.
What can you not give up: Large living room, large open kitchen. Lots of light in the house.

Why does the design look the way it does?
Terrace orientation southwest, building window