ᐅ Large single-family house with 4 children’s bedrooms – adaptable into 2 separate living units

Hello everyone,

we are planning a larger house to eventually accommodate four children, with the option for grandparents to move in later. Since the space requirement won’t be this high permanently, the house should be divisible into two separate living units – for example, for subletting, for an adult child with family (as we ourselves grew up), or for flexible use and better resale value. My parents live on the neighboring property to the north; we are trying to respect that (they want to stay there but are still independent).

I welcome honest, well-reasoned feedback – the more detailed, the better.

Plot and framework conditions

• Location: infill development, no formal building plan → orientation based on heterogeneous surrounding buildings
• Plot size: approx. 740 m² (about 8,000 sq ft), slightly elevated (approx. 1 m (3 ft)) compared to the street, then level
• Site coverage ratio: 0.4
• Floor area ratio: not specified, 2 full stories typical in the area
• Setbacks: 3 m (10 ft) to neighbors, up to 6 m (20 ft) at property boundary possible
• Edge development: only carports allowed
• Parking spaces: 2 required (driveway counts as second space)
• Roof type: pitched roof 23°, allowed range 20–45°
• Neighboring houses: height 7.8–9.2 m (26–30 ft) → planned building 8.81 m (29 ft)
• Orientation: street to the east, entrance planned to the north

Client requirements

• Style: efficient rectangular volume with pitched roof, flexible in appearance
• Basement: no (too many rooms that don't fit well in a basement)
• Stories: 2 plus attic for storage
• Residents: currently 2 adults, 2 children → eventually 4 children plus possibly grandparents
• Space needs: 4 children's bedrooms, 1 home office, 1 guest/grandparents’ room, kitchen, living area, utility/technical room, sufficient storage
• Kitchen: open plan with island, seating for 6–8
• Fireplace: no
• Balcony/terrace: no upper terrace, focus on garden
• Garage/carport: carport
• Kitchen garden: present but not a priority
• Size: preferably under 200 m² (approx. 2,150 sq ft) living space (tax benefits, lower running costs)
• Goal: position house as far south as possible so parents’ house to the south still gets sunlight

Design status

• Planning: done by independent planner for a fixed price → to serve as a basis for builder offers
• Current status: mostly final, last optimization round planned

What we like

• Room layout meets all requirements
• Utility room right next to bathroom (laundry without stairs)
• Large, bright open kitchen with plenty of storage
• Attic compensates for no basement
• Good size children’s bedrooms
• Overall efficient floor plan

What is still not ideal

• Hallway width (1.25 m (4 ft)) is rather tight
• Minor compromises in furnishing, but overall satisfied

Budget

• Planner’s estimate: 550–600 thousand euros (outdated)
• Our expectation: about 650 thousand euros
• Upper limit: 700–750 thousand euros
• Heating system: heat pump with underfloor heating

Priorities

• Essential: 4 children’s bedrooms
• Dispensable: some space or number of windows if necessary

Design development
We planned ourselves for a long time before hiring a professional planner. The process was an iterative one with back and forth optimization.

Furnishing
The living room still needs a large sofa and a TV on a shelf. The large wardrobes in the rooms probably won’t be that long; instead, desks will go there, for example. The bed likely won’t be in the home office. The kitchen island contains the stove and sink with a worktop between, and storage areas at the edge.

Special features
If the wall between the two western children’s bedrooms is removed, a full 4-room apartment is created on the upper floor (open kitchen/living area + three rooms + 2 bathrooms). The division would then be, for example, along the red lines shown. This greatly increases flexibility – for a granny flat, rental, or grown-up children later on. Even in the worst case (sale), the floor plan remains value-stable and versatile. Overall, the house feels like a very efficient realization of a large program of space – but we are open to any well-founded criticism or improvement ideas.

Specific questions:

• Floor-to-ceiling window in the bedroom or not (possibly desk space)?
• Is the small window in the upper hallway sufficient?
• Would an additional south-facing window for the children’s bedrooms on the south side be useful?
• The house is positioned quite close to the southern boundary – is that reasonable from your perspective (considering parents’ house to the south)?
• Utility room directly adjacent to the bathroom with prepared connections for a washing machine enabling possible separation of living units – practical like this?
• Should the wall between living room and kitchen be optionally designed as non-load-bearing? Likely costs around 5,000 euros more.

We look forward to comments on:

• Room layout
• Lighting/orientation
• Proportions/furnishability/daily usability
• Rental potential and value development
• Anything else you find relevant

Thanks for your input!

[ATTACH alt="Bildschirmfoto 2025-10-05 um 00.52.59.png"]93026[/ATTACH]

[ATTACH alt="hausansicht-einfamilienhaus-mit-pv-anlage-baum-bank-hund.jpg"]93029[/ATTACH]
[ATTACH alt="hausansicht-einfamilienhaus-mit-pv-anlage-baum-bank-hund.jpg"]93029[/ATTACH]
[ATTACH alt="Bildschirmfoto 2025-10-05 um 00.47.06.png"]93027[/ATTACH]

In the floor plan game, others get significantly more space. Basically, I like the flexible concept. Of course, there is the risk that not all features are fully achieved, and compromises have to be made.
However, from a quick review, I noticed the following:
- Omit the ring beams (tie beams) on the ground floor and install the windows including roller shutter boxes directly in the concrete ceiling so far
- You can do the same on the upper floor if you also design the upper ceiling as a concrete slab
- With a bit more reinforcement steel, it should be possible to make the walls between the kitchen and living room non-load-bearing. It shouldn’t cost more than about 5,000 (currency)
- Skip the skylight and plan to install photovoltaic panels over the entire roof surface. Light from the two gable windows is sufficient
- I would design the front part of the attic directly as a playroom and use the rear area as storage space
- In the guest bathroom, I would choose a shower instead of a bathtub

Marcus. schrieb:

We spent a long time planning ourselves and then hired a designer.

Whoever the designer is, they are not worth the money. It’s best to quickly throw that mess away.

I cannot see the first part of the plan. Where is the house supposed to be located on the plot?

You want to build a house for 4 children that can possibly be divided into 2 separate living units later and plan for 2 parking spaces, one of which is also enclosed? Just kidding, right?

In my opinion, the photovoltaic system is not well planned. Assuming the dormer windows have a north/south orientation, the south-facing roof should be fully covered. I believe you can fit 33 modules there. The north side should only be used if you have extra budget. From October to March, there is basically no yield from that side, which is needed by the heat pump. In my opinion, the roof pitch should also be a bit steeper, around 30 degrees.