Is this effort worthwhile for the tenants?

6.5cm sacrifice several square meters of living space in the basement? Hardly in a room of 30sqm.

Even if it is a 2m wide tube and thus 15m of wall, it is not even one sqm.

And then you have rooms there that have connections and are lying fallow? You do know that you are not allowed to connect dead lines to the system?

At the beginning, we also had the great idea to only prepare the bathroom in the basement... now there is a fully functional bathroom. We didn't want a space that was expensive to build to just sit there for years or even decades without any purpose. On top of that with a "forbidden" installation – do you really want to bring the mess back in later?

And then you have rooms there that have connections and lie fallow? You do know that you are not allowed to connect dead lines to the system?

That is true and should be taken into consideration by you.

At first we also had the great idea to only prepare the bathroom in the basement... now there is a fully functional bathroom. We didn't feel like having an expensive room built that just sits there unused for years or even decades, making no sense. On top of that, with a "forbidden" installation - do you really want to bring in the dirt again later?

We felt the same with our "kids' bathroom." Now the bathroom is completely finished, only the shower cabin is still missing :rolleyes:

However, such a granny flat also offers some advantages. We lived relatively cheaply for years in my father-in-law’s granny flat and were able to save up a significantly better capital stock for our house. :D

And then you have rooms there that have connections and lie fallow? You do know that dead cables are not allowed to be connected to the system, right?

That is probably the smallest problem. The dead cables probably run all the way to the utility room anyway and are not spur lines to enable separate meters, etc. So, they are simply not connected (only if they are really needed later).

If it's done that way, then ok - but one isn't even sure about the [Einliegerwohnung] ;).

The expansion of the bathroom only comes into consideration if my brother, who is studying, moves in. Otherwise, the connections just won’t be connected. That’s not a problem, is it?!

Here in the area, 30m² are rented for 300-400€. I don’t think that’s so bad. A lot of things are irreversible now anyway. We probably could have done without the separate entrance door. Well, maybe we’ll use the room as an office for self-employment someday, then it will have been good for something :)