Single-family house approx. 160 sqm flat roof - Optimization / Planning

Good morning,

the property has finally been purchased... now the actual planning begins. Attached is our first draft, which I would like to put up for discussion here. It is still very rudimentary, no windows/furniture drawn in yet, that will follow in the next step.

Development plan/restrictions

Size of the property: approx. 500 sqm
Slope: no
Site coverage index
Floor space index: 0.4
Building window, building line and boundary: distance of 3m from the property boundaries
Edge development: yes/no, garage 1m lateral distance, 5m front distance
Number of parking spaces: 2
Number of floors: 2 full stories
Roof type: -
Style direction: -
Orientation: -
Maximum heights/limits: TH < 6.2m; GH < 9.7m
further requirements

Requirements of the builders
Style direction, roof type, building type: flat roof
Basement, floors: no basement, ground floor, upper floor
Number of persons, age: 4 (two adults, two children)
Space requirements on ground floor, upper floor:
GF: open living/dining area with kitchen, pantry, utility room, bathroom with walk-in shower, guest room (later bedroom in old age)
UF: bedroom, 2 children's rooms, dressing room, 1 bathroom with walk-in shower, laundry room
Office: family use or home office?: no
Overnight guests per year: yes, about once a month over the weekend
Open or closed architecture: open
Conservative or modern construction: modern
Open kitchen, kitchen island: open kitchen with (freestanding) kitchen island
Number of dining seats: 6-8 persons
Fireplace: no
Music/stereo wall: yes, i.e. at the TV
Balcony, roof terrace: no
Garage, carport: yes, preferably double garage with storage/hobby room due to no basement
Utility garden, greenhouse: no (possibly raised bed)
Further wishes/special features/daily routine, also reasons why this or that should or should not be:

[*]Straight staircase (even if it takes up more space)
[*]From the kitchen, the dining area and living room should be visible

House draft
Who is the planner: Do-it-yourself
What do you like particularly? Why?

[*]Straight staircase
[*]Open kitchen/dining/living area

What do you not like? Why?
Price estimate according to architect/planner: -
Personal price limit for the house (including equipment): 350-400 thousand EUR
Preferred heating technology: air-to-water heat pump (underfloor heating)

If you have to give up something, on which details/extensions
-can you do without:
-can you not do without:

Why is the draft as it is now?
No architect involved yet, own planning based on inspirations from the internet, magazines and model/vacation homes

What makes it particularly good or bad in your eyes?

What is the most important/fundamental question about the floor plan summarized in 130 characters?

Thank you very much for your suggestions, criticism, etc.!

Without doors, orientation, and furniture, it's somehow quite difficult to say anything about that... Would you add those in?

Windows would also be nice

Draw furniture to scale. A double bed and wardrobe do not fit in the guest room downstairs.

Attached are the plans with doors, windows, and furniture.

Windows on the ground floor:
- on the left (west) all normal windows
- on the south at the dining table a lift-and-slide door
- on the south living room normal window
Windows on the upper floor:
- no floor-to-ceiling windows
- in the bedroom still open whether normal or clerestory windows
- in the children's room also still open (I think the rooms are big enough here to position the windows and furniture)

: The room downstairs will indeed be a bit tight if later a 2x2 m bed plus wardrobe is to be placed here. It’s also only for the "emergency," which hopefully will not occur. An alternative would be a stairlift or a smaller bed.

Smaller bed would be a single bed. A 160 cm for 2 at an age where at least 1 is severely limited does not work. Assistants of all kinds require space.

Is the [OG] recessed?