ᐅ Single-family home with an accessible granny flat on the ground floor

Hello everyone,
we are currently facing the challenge of planning a single-family house for a family of four, including a barrier-free basement apartment on the ground floor for my parents. The whole project is on a 550sqm (5920 sq ft) mostly flat plot, with the requirement not to build over the garden.

Development Plan / Restrictions
Plot size: approx. 550sqm (5920 sq ft)
Slope: no (approx. 0.5m (1.6 ft) height difference over 22m (72 ft) plot width)
Site coverage ratio: 0.4
Floor area ratio: n.a.
Building envelope, building line and boundary: 16m (52.5 ft) west-east + 3m (9.8 ft) boundary setbacks each side, 14m (46 ft) north-south, 5m (16 ft) setback to street in front of the house
Edge development: yes (north: public access road, west and south: bike path, east: neighboring development with a semi-detached house, currently vacant)
Number of parking spaces: 4
Number of storeys: 2
Roof pitch: 0-35°
Architectural style: no hipped roof and no Bauhaus style
Orientation: south-facing (garden)
Maximum heights / limits: eaves height 5.5-7m (18-23 ft), building height 10m (33 ft)
Additional requirements: The development plan reads as eaves height must be at least 5.5m (18 ft). Our design includes a single-story “extension” that falls below this. According to the building authority, the eaves height applies only to pitched roofs, and even a bungalow would be allowed here.

Client Requirements
Style, roof type, building type: preferably converted attic with a gable roof
Basement, floors: no basement, 2 full floors + attic
Number of occupants, ages: 4 for the main unit (2 adults aged 41, 2 children aged 9 and 7) and 2 for the basement apartment (80+)
Room requirements on ground floor and upper floor:
Ground floor: barrier-free basement apartment with bedroom, shower bathroom, living room, kitchen, optional small storage room (approx. 50sqm (538 sq ft)); main apartment: living-dining area, open kitchen, (small backup kitchen/pantry), guest toilet, utility/technical room
First floor: 2 children’s rooms approx. 15sqm (161 sq ft) each facing south, master bedroom with west-facing window plus a small dressing room, bathroom with T-layout accessible to all, children’s bathroom with shower
Attic: multipurpose room (fitness, office) + storage space due to no basement
Office: family use or home office? Home office
Guest rooms per year
Open or closed layout: rather open (not including open galleries)
Conservative or modern construction: yes
Open kitchen, kitchen island: both yes
Number of dining seats: 6 in main apartment, 2(-4) in basement apartment
Fireplace: no
Music/sound wall: no idea what that is
Balcony, roof terrace: roof terrace as a nice-to-have (see design)
Garage, carport: preferably on the east side next to the basement apartment
Utility garden, greenhouse: no
Additional wishes/special features/daily routine, including reasons for or against certain features

• Backup kitchen is a long-cherished wish of my wife and should not be missing.
• Utility room must provide at least 3 x 1.9m (10 x 6.2 ft) space for the heat pump and the hot water system connected to the local heating network. The room should also be used for washing and drying laundry.
• Children’s rooms facing south with about 15sqm (161 sq ft) each are mandatory.
• Building mass should not extend too deeply, to preserve garden space on the south side.

House Design
Planner: architect
What do you like? Why?

• Living-dining area plus kitchen fits our requirements. We saw it in a show home and immediately agreed we wanted it like that.
• The basement apartment is barrier-free, and the room layout basically fits well.
• No complaints about the first floor:


• Both children’s rooms are the same size (approx. 15sqm (161 sq ft)) and face south.
• Master bedroom is in the (north-)west with a west-facing window.
• Two bathrooms as requested.
• Converted attic as extra space for home office, fitness, and hobbies.
• The building is not too deep at 10m (33 ft), leaving enough garden space.

What do you dislike? Why?

• The pantry (backup kitchen) seems a bit large.
• The area around the staircase, door to the utility room, and guest toilet feels cramped and awkward.
• We actually like the straight staircase, but it is completely hidden, so only the stairwell is visible.
• The attic staircase is placed on the west gable side; we would prefer it centrally placed or at least on the north eaves side.
• No access from the basement apartment to the utility room (e.g., to do laundry).
• Garden shed currently planned in the southwest; if anything, it should go to the northwest for garden tools and bikes.

Estimated cost according to architect/planner: 500,000 (without attic)
Personal budget limit for house including equipment: 600,000
Preferred heating technology: ground source heat pump (local heating network is mandatory)

If you need to give up something, which details/extensions?
- What can you do without: garage
- What can you absolutely not do without: basement apartment

Why is the design as it is now? For example:
Which requests were implemented by the architect?
Primarily based on our wishes, which were mostly implemented already. However, we are especially bothered by the arrangement/design of the utility room, staircase, and pantry layout—at least on paper—as it’s hard to imagine this part clearly.

What makes it, in your opinion, particularly good or bad?
Fairly compact, as the entire ground floor area is not built over on the first floor.

And of course the development plan including our plot.