Terrace roofing semi-detached house - partition wall

Good day,

I have already read many posts but did not really become any wiser, so I am creating a new topic.

I wanted to inquire how it is handled in NRW regarding terrace roofs between semi-detached houses.
Initial situation:
The neighbor built a roof without asking beforehand. Which is basically okay with us. However, he did not install a closing wall between the terrace roof and the boundary wall, so the sound bundles very strongly.
I know that with a semi-detached house you are always very close to each other, but this strong noise development only came with the roof.
We spoke to the neighbor about it, and he only wants to do it if we pay 50/50, which I do not understand since it is his roof.
Furthermore, the thought of fire protection came to me, but I found a lot of conflicting information, so in the end, I was no wiser whether a fire protection wall up to the terrace roof is required for a terrace roof.

The roof is approx. 2m high, 3.5m long, and 7m wide. I also checked the design statutes and found the following:

Enclosures between private properties
As enclosures between private properties, chain-link or rod fences as well as hedges up to 1.80 m high above the upper edge of the terrain at the respective property boundary are permitted. Terrace partition walls are permitted on the common property boundary up to a height of 2.0 m above the upper edge of the terrace and a length of 4.0 m – measured from the rear building facade.

The rear building limits may be exceeded by single-story glass extensions/conservatories and terrace roofs by up to 4 m. However, a minimum distance of 3 m must be maintained towards streets, paths, and green spaces.

Thank you very much for the help.

And your question is? What do you want to know?

I would like to know if my neighbor is obligated to build this partition wall?

As I understand the design statute, he was able to build the roof without our consent. I found nothing stating that this must be done with a minimum distance from the property boundary, or is there a general law that applies here?
Does there have to be a terrace end wall or is it mandatory?

Talked to the neighbor about it and he only wants to do that

What?

I checked the design statute and found the following:

As I understand the design statute, he could build the roofing without our consent.

That applies restrictively to semi-detached houses. It should be stated in your development plan, because where semi-detached houses are explicitly planned, these exceptions are explicitly regulated. Otherwise, the state building code applies.

Does there have to be a terrace end wall or is it mandatory?

Neither, meaning it is not mandatory unless explicitly defined.

I know with a semi-detached house you are always very close to each other, ...

No, actually not. In fact, my first thought would be to move the terrace, if the property allows it.

Leaving legal matters aside. Since only you are bothered, I find a 50/50 solution from the neighbor very accommodating.