ᐅ Floor Plan Single-Family Home with Granny Flat as a Three-Unit Residence

Hello everyone,

I have been a quiet reader here for a long time and have gained a lot of information and ideas from this forum. Many thanks for that!

Since the end of last year, we have been looking into building a house. Initially, we spoke with a few turnkey construction companies. We moved forward with planning more concretely with one company. However, we were never completely satisfied with the results, as we felt the flexibility and individuality were always limited beyond a certain point. Meanwhile, we have turned to an architect from the neighboring village who will support us from planning to the finished house (phases 1-8). We have now reached the point of a "final" draft including a cost estimate.

Development plan/restrictions
Plot size: 709 sqm (7,630 sq ft)
Slope: No
Floor area ratio (FAR): 0.4
Floor space index (FSI): 0.8
Building envelope, building line, and boundary: see plan
Edge construction: garage
Number of parking spaces: 1.5 per residential unit (= 5)
Number of floors: 1.5
Roof type: 38-47° (100-116°F) gable or half-hipped roof
Style: No specification
Orientation: No specification
Maximum height/restrictions: None
Other requirements: None

Client requirements
Style, roof type, building type: Classic-modern, gable roof
Basement, floors: 2 full floors (according to development plan only 1.5 => however, neighbors in the immediate area have been granted permission for 2 as long as the overall height does not exceed 1.5, which requires a lower roof pitch)
Number of people, age:

• Currently: 3 (Dad 27, Mom 25, son 1)
• Future: 4-5 (Dad, Mom, 2-3 children) + 2 in granny flat (parents, in about 5-10 years)

Space requirements on ground floor and upper floor:

• Ground floor + upper floor:
• Size: approx. 160-180 sqm (1,722-1,938 sq ft); inspired by the new build of an acquaintance
• Rooms ground floor: open kitchen/dining/living area + small pantry, office, utility/technical room, guest WC
• Rooms upper floor: large bathroom, master bedroom, 3 children’s rooms
• Granny flat:
• Size: approx. 50 sqm (538 sq ft); based on our old 2-room apartment
• Rooms: open kitchen/dining/living area, bathroom, bedroom

Office: home office
Overnight guests per year: can sleep on the sofa
Open or closed architecture: open
Conservative or modern construction: modern
Open kitchen, kitchen island: open, kitchen island maybe
Number of dining seats: 6
Fireplace: provision for future installation
Music/stereo wall: No
Balcony, roof terrace: No
Garage, carport: garage, but also open to a carport (depending on savings)
Vegetable garden, greenhouse: No, possibly a small utility area in the garden
Other wishes/special features/daily routine, including reasons for choices or exclusions: None

House design
Who designed the plan: architect
What do you especially like? Why?

• Use as a single-family house plus granny flat, with the option to separate into 3 units later, e.g., when children grow older or if renting is desired
• Separate garden areas for the main house and granny flat
• Large windows facing south => lots of daylight (neighbor to the south is quite far away + good privacy to the east thanks to granny flat)
• Garden/terraces on the south side
• Direct access to the garage from inside
• Direct access to the granny flat for times of sole family use

What do you dislike? Why?

• Very dark entrance area
• Concern that the kitchen/dining/living area might be too small or cramped

Cost estimate according to architect/planner:

• Note: everything calculated very generously based on current raw material prices
• All-in: 778k (we already own the serviced land)
• of which 40k are additional construction costs
• of which 35k already planned for furnishings
• of which 50k already planned for outdoor facilities and open spaces
• Resulting in:
• after deductions for subsidies: 662k (3x KfW 40 Plus + energy consultant = 116k)
• after deductions for assured DIY work: 642k
• after deduction of approx. 160k for granny flat (financed by parents): 482k

Personal budget limit for the house, including fittings: Is it even possible to define this nowadays?
Preferred heating system: heat pump

If you had to give up something, which features/extensions
- you can live without: fireplace (or just fireplace preparation), smart home (I’m an IT professional and can retrofit it myself later)
- you cannot live without: none

Why does the design look as it does now? For example:
Standard design from the planner? Basic idea is ours + several discussions with the architect
Which wishes were implemented by the architect?

• Almost all of our wishes
• Staircase with straight steps

What makes it particularly good or bad in your opinion?

• Good: not a run-of-the-mill standard design, visually very appealing (in our opinion)
• Bad: nothing

What is the most important/basic question about the floor plan summed up in 130 characters?

• We would simply like some unbiased opinions/optimizations from third parties
• How can the entrance area be improved in terms of natural light?

Do I understand correctly that the granny flat is only planned to be used as such in about 10 years, and until then the unit will be used as living space?

Actually, you are only building two residential units. The third one can be separated later (kitchen connections still need to be prepared), but I don’t see the third one qualifying for funding at this point. Otherwise, I don’t think it’s bad.

I would have planned the kitchen island differently, as you always have to walk around it while working. The open-plan living area of the granny flat might not be very cozy. Where and how are the parents currently living? Is the granny flat designed to meet their needs?

Myrna_Loy schrieb:

Do I understand correctly that the granny flat is planned to be used as such only in about 10 years, and until then it will be used as living space?

Exactly. We would use it as a (admittedly oversized) office for now. It doesn’t make much sense to start another construction project for an extension in 5-10 years when I already know it will happen. Besides, construction costs will probably be even more insane by then than they are today. The alternative would be to rent it out until then. But we would only do that if there really was no financial other option. Do you have a better idea? If so, please share 🙂

Ysop*** schrieb:

Actually, you are building only two dwellings at first. The third unit can be separated later (kitchen connections would still need to be prepared), but I don’t see the third unit qualifying for funding right now. Otherwise, I don’t think it’s bad.

I would have planned the kitchen island differently since you always have to walk around it when cooking. The open-plan space in the granny flat might not be very cozy. Where and how do the parents currently live? Is the granny flat designed to suit their needs?

Thanks for the feedback! On the plan, there are indeed still two dwellings. One of the upstairs bedrooms will be converted into a kitchen. The connections for that will, of course, be prepared. That will bring us to three units.

I have to admit, I’m not fully happy with the kitchen island either. I already found the walking-around issue a bit annoying. But we would probably make the island narrower—around 1.20 m (4 feet) instead of 1.60 m (5 feet 3 inches). We’re still unsure if that would help significantly. The alternative to the island would be a U-shaped kitchen. However, that would mean giving up the floor-to-ceiling windows and losing the (in our opinion) beautiful large glass front.

/edit: Sorry, I didn’t answer half of your questions earlier. Here’s the rest:

The parents (both in their early 60s) currently still live in their own house. Since the kids have moved out, much of it is unused. They already know that as they get older, they will not be able or willing to maintain and manage the entire house anymore. Additionally, it is not very age-friendly and has a rather impractical staircase. Hence, the wish for step-free living, which we have taken into account in our design. The house will be sold when they move into the granny flat.

I think the design is good – the architect really did a great job. However, the overall concept feels unfamiliar to me.
I assume the parents are still relatively young? And the move-in is planned for around age 60?
The granny flat, as it is currently laid out, is not accessible for people with disabilities at all. I always find it difficult to deal with these all-in-one house concepts. If the ideal scenario doesn’t happen, you end up with three people living in 230 m² (2,475 sq ft) and dozens of rooms. I have seen many single-family homes where the plan was originally to rent out part of the house later – but nobody actually does that. People usually don’t want strangers so close in a single-family home. It’s like a shared flat.

The plot looks good, with a southwest-facing garden and driveway on the northeast side, which I like. The rest not so much 🤨

The kitchen seems impractical to me, equipment too small for a multi-family house, hallway upstairs without a window but with a door to the stairwell.

It gives me the impression again that instead of creating a truly nice living unit, there is a forced attempt to fit in 3 apartments even though currently only one is actually needed.
Are you by any chance related to @Felix85? :p