Plot for construction next to existing building - "Single-family house in Grandma's garden"

Mhh you should really deal with the topic much more intensively; it seems you lack any basic knowledge. Study the local building regulations calmly. - that should help at least.

mhh You should definitely engage much more intensively with the topic; it seems you lack any basic knowledge. Study the local building regulations calmly. - that should already help.

Thank you, I will gladly do that. It is actually still unclear to me why the construction of a garage on a boundary that does not touch "our" property but is adjacent to it has an impact on our possibilities. But I will gladly try to find out and also check whether this is recorded in the land register.

What you can always do is submit an informal building inquiry. Here you can simply present your idea to the building authority and they will then basically respond to it.

I understood it this way: You have to have the plot divided so that the house on it will later belong to you. The house belongs to whoever owns the plot. Thus, the garage is located where the imagined new boundary of "your" plot will run later. And here too, distances must be maintained.

[*]Preservation of the double garage

Wash me, but don’t get me wet!
That’s a nice thought from grandma, but the garage is located centrally on the property. If another house is even approved, it has to be removed or "inhaled". Sorry, I have to vent about this: who ever planned that? It could only have been a man! :rolleyes:

The garage will have to be removed. Otherwise, I don’t see any real solution.

I don’t want to seem disrespectful, but how old is grandma?
Let’s not have it spread that grandma is disappointed about the loss of the garage, that there have barely been any compromises since she moved in, and now grandma has to leave her house.

I would first read the development plan. Then you’ll know with which distances, floor area ratio, site coverage ratio, ridge heights, etc., you can plan.
Then you’ll know how and whether a house, as you need it, can even fit on the divided plot.