ᐅ Improvement Suggestions for a Single-Family Home with 137 sqm of Living Area and a Secondary Apartment

Hello, we are planning our house, which we want to share with my mother (separate apartment approximately 70 sqm (750 sq ft)). We want to maximize the floor area with 137 sqm (1,475 sq ft). Maybe someone has ideas, suggestions, or improvements. We are grateful for any input.

Development Plan / Restrictions
Plot size 459 sqm (4,940 sq ft), 21.5 * 21.4 meters (71 * 70 ft)
Site coverage ratio 0.3
Building area 15.4 * 13.4 meters (50 * 44 ft)
Building line 3 meters (10 ft) and boundary line 5 meters (16 ft)
1.5 storeys
Roof type: steep roof, minimum 35 degrees
Street-facing gable
Maximum heights / limits 9 meters (30 ft)
Other requirements: max 1.15 meter (3.8 ft) knee wall

Owners’ Requirements

2 storeys + expandable attic
Upstairs: 5 people, including three small children. Ground floor: 1 person, mother
Space requirements ground floor
Mother’s apartment: 2 rooms + living room + open kitchen,
separate office with WC.

Space requirements upstairs: 3 children’s rooms, master bedroom, open living and kitchen area, two bathrooms

Office: home office, possibly for visitors

Conservative construction
36 cm (14 inch) masonry
Open kitchen, kitchen island upstairs
Number of dining seats upstairs 6-8
Possibly a balcony
Garage added later
Staircase to attic with roof window accessible from both households

House Design
Designed by:
- Do-it-yourself
What do you dislike? Why? Dark corridor
Personal budget for house including fittings: 400,000
Preferred heating system: heat pump

Why is the design like it is now?
What do you think is particularly good or bad about it? Maximum size utilized, difficult implementation due to sloping roofs

Thank you, maartina

Please seek professional planning assistance. I would definitely not proceed with this. Even if you probably disagree, there are so many inconsistencies that it’s really not worth getting into a deeper discussion. Sorry if this sounds harsh.

The budget including additional building costs will not be sufficient.

Measurements are missing.

To my knowledge, the building with the outbuilding is too large.

Are you planning for 1.5 or 2 stories?

Draw furniture to scale and include doors in every room.

If I interpret the regulations correctly, the upper floor can only have a knee wall height of 115 cm (45 inches). This means the whole design probably can’t be realized as planned. Unfortunately, the few measurements are not even legible yet. The north arrow and site plan are also missing.
A garage for 3 cars… takes up quite a lot of the floor area.

The budget should be sufficient, at least that’s what we have heard from various construction companies and architects. The knee wall height is limited to a maximum of 115 cm (45 inches), and for the bathroom, we are planning a dormer or something similar.
It will probably end up being a double garage, but this will likely be added at a later stage.
The house currently measures 10 by 13 meters (33 by 43 feet).
A one-and-a-half-story design is required, which is why we have difficulties achieving a reasonably sized living area upstairs, let alone decent room sizes.
We have already had architects draw up plans, but each time we had to accept significant compromises.

Always draw a 2 m (6 ft 7 in) line
Correctly scaled furniture
In a bedroom and bathroom, not even doors fit

Without additional construction costs and garage, the budget might work. Not all-inclusive

Yard, terrace, and garages must be considered in the floor area ratio. Others might know better to what extent. This is too large

Regardless of the budget. An office with client access, a secondary apartment, and an apartment for a family of five require quite a lot of space.
In addition, no garden access for the family yet.
Garage, parking spaces, terrace, etc. on the small plot

Basement for office with light well, building services, and storage areas
Ground floor secondary apartment—how barrier-free/accessible should this be? It would be good to have cooking/dining with garden access for the main apartment
Top floor sleeping, living