Attic not fully registered as living space - NRW

Thank you very much for your constructive advice!
According to your contributions, here are a few remarks:

Who is interested in how you use your rooms. Formally, it is then not living space for permanent residence, but "only" a furnished storage room. Be pragmatic

I am not an expert... But I know, for example, that insurance companies sometimes look very closely when you want something from them. Suppose something stupid happens to me there and I want the insurance to handle it. Can't they then say "But otherwise you’re fine? Why are you sleeping in the attic?"

The only important thing is that living space is also living space (e.g. room height, lighting, escape routes, etc.)
P.S. How does the tenant get to the bathroom if you don’t want to rent out the "attic"?

Exactly - according to the building authority, the "attic room" is simply not living space... Still, it seems exaggerated to me to enlarge windows or dormers just because of this single room, or to engage an architect to submit a building application.
Regarding the P.S.: Hehe yes... Maybe I would then have to rent the apartment without a bathroom! But – now it’s getting subtle – wouldn’t the landlord be allowed to use the "attic room" as a storage room if I clearly regulate that in the rental agreement?

You are guessing a lot right now. Please clarify whether an extension is possible under building law and if so, how the extension may/must look (possibly change of use).

I have already been to the building authority. That’s where the terms I use here come from. I am only asking further here because I’m looking for "loopholes." They just say "Engage an architect, submit a building application. Probably windows too small. And possibly insufficient soundproofing and thermal insulation." What bothers me about this is the lack of proportionality. Except for this #!*$ "attic room," the rooms are already declared as living spaces!

Where there is no plaintiff ...

OK, so you see the private use as living spaces by us (only we live in the house) as unproblematic? That would be a good start...

OK, so do you see the private use as living spaces by us (only we live in the house) as unproblematic?

But absolutely unproblematic! I would leave renting out with all the open flanks alone.

As far as I know, the rule in such cases is: rented as seen. This means the tenant cannot make any claims if they later find out that the apartment is not an official living space. Problems only arise if the building authority prohibits the use, because then the landlord owes the tenant an apartment that he cannot provide.

Hello,

we have also converted our 1.5-story house. The upper floor was divided into a master bedroom and one half as an attic. When we bought the house, we converted the attic and made 2 children's bedrooms out of it (each 25 sqm).

I also went to the building authority and was told that I do not need a building permit, but I did not receive anything in writing!

As far as I know, the rule in such cases is: rented as seen. That means the tenant cannot make any claims if they eventually realize that the apartment is not official living space.

That is unfortunately not correct. The living area is then, for example, 0 sqm and the tenant can reduce the rent to 0. Not to mention claims for damages.

Why should the tenant be allowed to reduce the rent? He still receives what he rented.