Duplex house for 3 generations? Or better tips?

Hello everyone,

I will simply describe our difficult case:

We (a young family) would very much like to have our own home soon (we currently still live in a rental apartment).
My parents own an almost 900 sqm plot near Regensburg, where there is currently a house from the 1950s (only a wood stove, no heating system, as you would expect from that time). My parents live on the ground floor, and my grandmother lives on the first floor (the attic is partially developed but without water supply). Together with an architect, we have already created a plan for the complete expansion of the attic, but this is not an option for us due to the small living area of only about 50 sqm.
Our idea would therefore possibly be to demolish the old house and build a semi-detached house. One half for the "young family" with 2-3 (?) children's rooms, the other half with the ground floor for my parents and the first floor for grandma.
However, we currently cannot really imagine what kind of floor plan would make sense here (especially with the semi-detached house split into two apartments). That is just an idea for now. Does anyone know a similar case or know of semi-detached houses that are divided into two apartments?
We do not want to commission an architect for this idea yet, as we have already incurred costs for the first idea with the attic expansion and the budget is naturally limited.
An extension/renovation of the current house is also something to consider, but at the moment we can’t really imagine whether this still makes sense with such an old house...
We do not necessarily want to keep the old house and just build a new house in the garden for ourselves, as there would not be much garden space left then.

Our plot measures about 20 m x 40 m

Does anyone have any tips or ideas for us?
We look forward to any response.
Thank you :)

Take a look at floor plans for multigenerational houses. The ground floor has two accessible living units and you live on the upper floor.

Semi-detached houses are basically end-of-terrace houses that are rather not intended as two-family houses (i.e., for maisonettes). Now, semi-detached houses do not necessarily have to have equally wide halves, so it would definitely be possible to plan one semi-detached house half in a "typical width" and the other in a width suitable for maisonettes (which your plot would allow, without knowing the building envelope, just saying).

Spontaneously, I tend to think more in another direction: somewhat similar to a semi-detached house, but with grandma in the middle on the ground floor, so three units on the ground floor and two units on the upper floor. Separate ownership units / parcels are probably not so important here (?)

Those who are already "grandma" now seem to me not so well "placed" in the future on the upper floor.

Haydee's proposal also seems worth considering to me.

At the top of the floor plan section there is a questionnaire. Please fill it out here and attach a development plan excerpt of the plot (or just the cadastral extract if it is a §34 area). Then we can discuss on a clearer basis.

We can also examine the current floor plans to see if they could be sensibly integrated into a new building.

An interesting project! :-)

For finding the floor plan, you should clarify the financial circumstances and (emotional and physical) expectations of all family members. Who contributes what, who owns the property, etc.

If I understood YPG correctly, she would halve the ground floor and accommodate parents and grandma there. You then throughout the entire upper floor (and possibly even the attic). I think that would be a very sensible consideration because grandma is probably the person most likely to have difficulty climbing stairs first. And you would have within your living unit fewer stairs to climb.

Emotionally interesting here is certainly whether the people concerned would even move or if they are so rooted in the existing house that a demolition is out of the question for them. A solution should also be discussed for the construction period if the current residential building is indeed to be demolished before the new house is ready. This is not only logistically interesting but depending on grandma’s attitude, she might not want to go through "something like that" at all.

In addition, you should consider how the respective living units are to be used once the relevant party or parties move out or pass away.
If the multi-generation household is then dissolved, the subsequent use should be reasonably possible without much effort.

I would then make these parameters dependent on how the persons are "distributed" within the different floors in the event of a new building.

P.S. (I won't use "Edit" since another post has already been added):

Together with an architect, we have already created a plan for the complete conversion of the attic, but this is not an option for us due to the small apartment size of only about 50 sqm.

That an attic floor is typically significantly smaller than a standard floor is actually common knowledge and one doesn't only realize that when planning (?)

An interesting project!

If I understood YPG correctly...".

Oops, I haven't written anything yet [emoji6]
Anyway.
I would probably first reconsider how old the generations are and what their needs are.
Grandma is probably poorly accommodated on the upper floor, just like the parents.
What are Grandma's requirements?
And the parents? How old might they be?
I think you won't get far with a standard floor plan or a typical house.
There are semi-detached house forms where an older party lives in 2/3 of the ground floor, the younger family in 1/3 of the ground floor and the entire upper floor.
But there are also four-family houses that look like semi-detached houses, with two entrances and a staircase behind them leading to one apartment each.
Then you also have to consider to what extent the individual groups want to live together.
If, for example, Grandma is no longer spry and eats with the "parents," then you could build the middle generation a ground floor where an open room with a bathroom for Grandma branches off at the front. But much floor space would be lost for the house.
That would not be a problem if you could regroup upstairs, including a balcony or roof terrace.
For example, space requirements on the ground floor: Grandma 40, parents 80, you upstairs 120.

!!!However, it depends on what can be built on the plot -> plot ratio, floor area ratio, number of apartments...
Number of stories, etc....!!!

I would have other concerns... my great-grandmother also lived in a 50s house upstairs with my grandparents. They shared kitchen and bathroom.
To me, they felt very old... Grandma lived with Grandpa in a semi-detached house of about 55 sqm, great-grandma in the attic of about 30 sqm, one kitchen on the ground floor, the bathroom upstairs.
That worked. My grandparents were probably around 65 at that time, my great-grandmother maybe 85.

My parents, now older than my described grandparents, now mid-70s (75), live alone in a 160 sqm single-family house and would no longer want to live with anyone else, give up their rooms, take someone in, and even less so live with someone from the family.
That also means: They would not want to live under 109 sqm if they wanted to move. At 75.

Where do your parents stand? Your grandma?

And even more importantly: what do they want? What are their needs?

And: demolition and new construction means at least 1.5 years of interim living...

So you can't really give advice now because you don't know your circumstances. Do you live as a large family or do you all prefer to be on your own?

My advice:
1. Hire an architect who can get everything possible out of the plot.

Possibly:
2. 2/3 of the ground floor for the parents, 1/3 for you for the entrance, staircase and utility room, the entire upper floor for you. For Grandma, some kind of extension/pavilion that can later possibly be rented out or used as an office/practice.
Possibly the option to separate differently later.
If the parents have just turned 50, they might currently favor a small semi-detached house with stairs, you the larger one. Grandma again in a single-level extension. Later horizontal separation.
Possibly one really has to think more in L- or T-shapes, enabling several apartments with one or two entrances that can be changed later.
But that should only be done by an architect.