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

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

Since we need an accessible apartment for ourselves in the short/medium term and an age-appropriate apartment for my father, we thought about renovation/remodeling.

Oh, accessible for you, age-appropriate for dad. The former would have to include the latter. I don’t see the apartment as suitable for aging: too many slants that make the space tight and reduce the living area. Since we don’t know WHY your unit MUST be accessible in the short term, I would advise you to carefully examine what actually needs to be accessible now and why. Crutches, pain, or wheelchair are reasons I consider, which would have to 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 place for the wheelchair. In your case, the bathroom is now not accessible and suitable for a helping hand. And many doors are arranged so that you would bump into cabinets rather than hiding them better behind doors. So: reflect on this yourself or tell us the reason so we can think along.

About the floor plan: swap the utility room and guest WC entrances due to the WC window placement, so WC moves to the bottom of the plan. Office possibly bigger. The furnished pantry is and remains later a small closet where people are 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 lower wall of the kitchen and experiment with the space and partition walls. Some nice ideas might come out (Danwood can do that) But I would rather swap kitchen and office. *And then I would consider whether instead of a double garage, a room for dad could be included on the ground floor or whether the property allows for two ground-level entrances, child or office or bedroom upstairs or ... is there a basement or slope?.., so there is some room to play with. By the way, there are good bungalows online that are different but would still fit well. And reserve space can be nicely placed above the garage if desired. Then the living space upstairs also relaxes a bit.

Since there is no development plan, the building area should only be restricted by minimum distances, or am I wrong?

I am under the impression that there is a de facto building area in your site plan.

Hanse Haus Bungalow 133 is barrier-free. There you can, for example, look at the bathroom and the bedroom. It works with a walker/wheelchair. Although a room is missing and the kitchen is open, it is still an example that works

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

Can you explain that in more detail?

Regarding accessibility: 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 take a few steps without aids for a long time, maybe a walker will suffice. Unfortunately, this cannot be said for sure, nor can the timeframe be specified. 2 years or 10 years. Everything is uncertain. This point and the poor existing condition led to the construction considerations. Moreover, I want to create a beautiful home for the family. Due to health limitations, we/she will of course spend a lot of time at home. Vacations will also no longer work as easily, etc.

If any information is still missing from me, just let me know. I had simply considered the background not so important and did not want to unnecessarily inflate the "story" around it. That it obviously helps to put yourself in our situation is also logical.

I will respond to the rest later with more time and peace.

Many thanks to you all in advance. The effort you make and the resulting feedback are great!

Can you explain that in more detail?

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

I simply considered the background as not so important and did not want to unnecessarily inflate the "story" around it.

Even if in individual cases youth can be more frail, with a view to the future I would not "shove a (still) spry senior under the roof." But that is related 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? 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 with an annex like the Allkauf Haus Prestige 2 V2. Better to park the cars under a tree.