ᐅ Floor plan design for a single-family house with 4 children's bedrooms and a self-contained granny flat/apartment

Hello everyone,

After much consideration, we have decided to build a house with a granny flat (accessory apartment).
Recently, I received the floor plan draft from our architect. Due to the small plot size and my lack of experience, I would like to ask for your assessment and suggestions for improvements.

Building Plan / Restrictions
Plot size: 435m² (about 4,681 sq ft)
Slope: no, but has to be filled to be flush with the street
Site occupancy index (floor area ratio): 0.25
Floor space index (plot ratio): 0.55
Building envelope, building line and boundary: 9 x 12.11m (about 30 x 40 ft)
Edge development: garage -> yes
Number of parking spaces: 2
Number of floors: 2 full floors
Roof shape: symmetrical gable roof
Architectural style: open
Orientation
Maximum height / limitations
Other requirements

[U]Client Requirements[/U]

Architectural style, roof type, building type
Basement, floors: yes, 2
Number of occupants, ages: 6, (40-35-12-9-7-5)
Space requirements for ground floor and upper floor
Office: family use or home office? family use
Number of annual overnight guests
Open or closed architecture: open
Conservative or modern construction: doesn’t matter
Open kitchen, kitchen island: doesn’t matter
Number of dining seats: 8
Fireplace: yes
Music / stereo wall: yes
Balcony, roof terrace: yes
Garage, carport: yes
Utility garden, greenhouse: yes
Additional wishes / special features / daily routine, including reasons why certain things should or should not be included:
Space for the family; parents’ bedroom can be small; granny flat will be rented out; exposed roof truss

[U]House Design[/U]

Planner: architect
- Planner from a construction company
- Architect
- Do-it-yourself
What do you particularly like? Why?
What do you not like? Why? TV area on the ground floor
Price estimate according to architect/planner: 450,000€
Personal budget limit for house including fittings: 420,000€
Preferred heating technology: air-to-water heat pump + photovoltaic system

[U]If you have to give up something,[/U]

Which features/expansions can you do without: upper floor parents’ bedroom can be smaller
Which features are essential: every child has their own room

[U]Why is the draft designed the way it is?[/U]

For example:
Standard draft from the planner?
Which wishes were implemented by the architect?
A mix of many examples from various magazines... yes
What do you think makes it particularly good or bad?

[U]What is the key/basic question about the floor plan in 130 characters?[/U]
I have read extensively in this forum and mentioned the ideas to the architect. I would like to thank everyone warmly at this point. I am open to any criticism or arguments.

Attached are the images.

Is the secondary apartment intended to serve as a fourth child’s bedroom? Otherwise, isn’t one still missing?

You won’t be able to build the house within your budget...

I'm not sure if you are allowed to build that large. The auxiliary structures still need to be considered. @Escroda, could you please take a look at this?

Where is the fourth children's room?
The budget is not sufficient.

Octrineddy schrieb:

Is the granny flat intended as a fourth bedroom? Otherwise, one is still missing, right?

It’s probably the room on the ground floor (utility/sleeping).

Almost 300 sqm (including the basement) for the requested €420,000 including photovoltaic panels, kitchen, fireplace, and whatever else. Impressive! Normally, we calculate around €2,XXX per sqm (square meter) of living space plus basement, additional construction costs, fittings, and garage/outdoor areas. This doesn’t add up.