Floor plan / planning of a single-family house with a granny flat on the upper floor

I imagine seeing an actual building envelope in your site plan.

My wife is ill and in the worst case will be in a wheelchair in a few years. Maybe she will still be able to walk a few steps without aids for a long time, maybe a walker will suffice. Unfortunately, you can’t say for sure and the time frame is also uncertain. 2 years or 10 years. Everything is uncertain.

In §34 areas, a building envelope is often derived from the front and rear edges of the existing buildings on a street, from which new buildings should not break out.
How is the site plan to be understood at all: does it show the new plot with an existing building that is to be demolished, or that of the existing house, and the new one is supposed to be placed in the garden, or what?

Even if in individual cases the youth may be more frail, looking to the future I would not "shove a (currently still) spry senior up into the attic." But that relates to the question of what is to become of the current house.

I understand what you want. Does your wife need the office?
How much space does the senior need? It bothers me to pack him into the attic. If new, then do it properly.

I would try to combine a bungalow like the Hanse Haus with stairs to an attic studio with an extension like the Allkauf Haus Prestige 2 V2.
Better to park the cars under a tree.

and Dad can still live to be 90 years old.

The plan shows our current house and outbuildings, which are to be demolished, and in their place, the new house is to be built.

I think the floor plans lack accessibility. If you make the small rooms/hallway wider and larger, the house will become unaffordable.

Oh dear, accessible for you, age-appropriate for Dad. The former would have to include the latter. I don't see the apartment as age-appropriate: too many slants that restrict the space and reduce the living area. Since we don't know WHY your unit must be barrier-free at short notice, I would advise you to carefully check what exactly has to be barrier-free now and why. Crutches, pain, or wheelchair are reasons I see, but these could/should be implemented differently. Also the question of who in the family needs the accessibility. We once discussed a bungalow here where the child is disabled. It was important that the child's room was connected to life. For that, the utility room had to be less accessible. But there always had to be a standing space for the wheelchair. In your case, the bathroom is not barrier-free and suitable for a helping hand. And many doors are arranged so that you run into cupboards rather than hiding them better behind doors. So: reflect on this and judge yourself* or tell us the reason so we can think along.

Regarding the floor plan: swap access to the utility room and guest WC because of window placement in the WC, so WC at the bottom of the plan. Possibly make the office bigger. The furnished pantry is and remains later a tiny closet where someone is supposed to sleep? I would drastically shorten the hallway to the private rooms and make it accessible from an "eat-in kitchen," so remove the kitchen's lower wall on the plan and play around with the space and wall panels. Some nice ideas could come out of that (Danwood can do that). But rather, I would swap kitchen and office. *And then I would weigh whether instead of a double garage, a ground-level room for Dad could be added or the plot allows for two ground-level entrances, child or office or bedroom upstairs or ... is there a basement or slope? ..., so that there is something to play with. By the way, there are good bungalows online that are different but would fit well. And a reserve room can be nicely accommodated above the garage if desired. Then the living space upstairs also relaxes a bit.

Me too... probably it's the western backyard, but that hardly plays a role here



Ok, then, for example, the shared bedroom belongs downstairs and the associated bathroom barrier-free, including wheelchair accessibility and with a helping hand, so quite square, not 2.40 in length.

First of all, I would distance myself from the "bungalow" idea. That does not mean giving up on single-level living. But the ground floor can also work as a "normal one-story single-family house" (which laypeople like to call 1.5 stories). For that, of course, as planned, parents' bedroom with the mentioned bathroom on the ground floor, and for you the bitter pill, to move the guest/office to the upper floor. The child too. Why? So that the footprint still leaves a small unit for the senior. You told us the roommate’s age is 62, but age is relative and doesn’t get better, so at move-in 65. I would actually go for a multi-functional floor plan, that is main area (living area, kitchen, bedroom, and bathroom with utility room), then an annex, which is initially separate but can later be opened to the main area (maybe the worst-case scenario: dad dies, wife needs outside help, possibly to be brought into the house), and the attic, which can be designed autonomously if necessary (maybe there, if the child moves out, then the help, dad still lives in his apartment)... all of this because you already have this barrier prognosis hanging over you and dad could still live to be 90.
Also all doable in an L-shape, with a private outdoor area for the apartment, possibly an exit onto this addition for the upper floor.
I would get a capable architect to plan a house for you as needed (and not one of those type houses changed by a layperson), which your building authority can then build.

That is also in a sense a "worst case": you don’t want to skip the move to a senior home for your ninetieth birthday just because it got too strenuous to climb up to the attic.

Logistically, that means one year in a transitional apartment.

I understand what you want. Does your wife need the office? How much space does the senior require? I am reluctant to put him under the roof. If new, then properly.

I would look to combine a bungalow like the one from Hanse Haus with stairs to the studio attic and an extension like the Allkauf Haus Prestige 2 V2. Better to park the cars under a tree.