ᐅ Single-family home with an accessible granny flat on the ground floor
Created on: 30 Sep 2025 12:03
W
WoodyXYZ
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
House Design
Planner: architect
What do you like? Why?
What do you dislike? Why?
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.
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.
The design won’t work within a budget of 600,000 including the garage. From experience, building right up to the limit doesn’t work; it always ends up costing more than planned, especially if you suddenly decide to add a KNX system for 50,000.
Take a look at the Allkauf House Generation 5 BF (barrier-free). Its somewhat more compact design fits better within your budget. I also think the granny flat has some good features.
Consider all scenarios in advance. How and for how long your parents will stay. Short-term care and respite care mainly exist on paper.
By the way, we use our unfinished attic as storage; our large inflatable exercise mat is there, as well as a Carrera racetrack and Gravitrax set set up. The advantage is that the dads and kids are upstairs, and we women can sit comfortably and quietly downstairs.
Take a look at the Allkauf House Generation 5 BF (barrier-free). Its somewhat more compact design fits better within your budget. I also think the granny flat has some good features.
Consider all scenarios in advance. How and for how long your parents will stay. Short-term care and respite care mainly exist on paper.
By the way, we use our unfinished attic as storage; our large inflatable exercise mat is there, as well as a Carrera racetrack and Gravitrax set set up. The advantage is that the dads and kids are upstairs, and we women can sit comfortably and quietly downstairs.
WoodyXYZ schrieb:
We didn’t just go to the architect and say, “We are 2 regular, 2 small, and 2 elderly people and need a house,” right? That is exactly what I would have recommended to you.
WoodyXYZ schrieb:
The shift was not present in the first preliminary design (Yes, you wouldn’t have called it that either), With properly executed design methodology (young people have always believed they know better), there isn’t a serial sequence of preliminary designs, but rather parallel preliminary designs A to C (less often only A and B, and more rarely up to E), from which the best choice is made, followed by a resting phase of the design, per my recommendation. After that, one (1,000!) preliminary design matures into the final design: phase 3 (development of design) is too expensive to waste time on trivial iterations here. “Modern” architects of the CAD generation consider it customer friendly to endlessly iterate, but they are actually doing the client a disservice. And general contractor draftspeople are well known for cutting costs in the wrong places anyway.
WoodyXYZ schrieb:
Here is an excerpt from the municipal utility company’s technical guidelines: “The equipment room for the WEA must be located on the ground floor or basement and must be accessible through publicly accessible rooms such as stairwells. Locating the equipment room on an upper floor is not permitted.” An inquiry with the municipal utility company also confirmed that installation on an upper floor will not be approved. The municipal utility company only has an advisory, non-binding private opinion in the procedure. The permitting authority may only apply this opinion within the legal framework. Sometimes it requires a judicial body to remind the responsible administration of the generally binding principles of proper administrative procedure; which must also be purposeful and reasonable.
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