Building law: Semi-detached house with an extension for a utility room as a garage

Hello everyone, I have only been an inactive reader in this forum so far, but now I need some advice myself.

Is it allowed to build an extension within the setback area (3m from the neighboring property) in the form of a garage (with a door into the house), but use it as a utility/technical room, or will the building authority not approve this? I have heard that a shed in the size of 3x6m or 3x9m is _allegedly_ possible.
In case anyone is wondering why not simply build a garage directly, the parking space for the car is already located elsewhere.

Best regards and thanks

Here (BY) I may also subsequently erect something 9 m long and 3 m high. After consultation with the building authority and coordination with the neighbor. Ergo your contact is the building authority. Then the neighbor.

Is it allowed to build an extension within the setback area (3m to the neighboring property) in the sense of a garage (with a door into the house), but use it as a utility/housekeeping room...?

Starting from NRW, §6, paragraph 8, Building Code NRW 2018 states what may be built within the setback areas. Since even the responsible ministry has recognized how ambiguous the wording in the law is, there is a recommended course of action on the ministry’s website as well as at the architects’ chamber aknw.de, which sheds light on this issue.
If you are hoping for more concrete help here, you need to be specific as well, for example with a site plan including dimensions, planned and existing buildings with actual and planned use, neighboring buildings, information on any building obligations and development plan determinations.

Utility/housekeeping room

Is a non-specific usage designation. It makes a difference whether the room contains a heat pump or an oil burner. And a housekeeping room is regularly considered a living space.

... or will the building authority not approve this?

A building or a garage is exempt from approval under certain conditions (§62, paragraph 1, no. 1 a) and b)). Compliance with all regulations then lies solely with the builder. A frequently occurring but nonetheless illegal case would be the use of a garage as a workshop or party room.

Here (BY) I would also be allowed to subsequently build something 9 m long and 3 m high.

But no lounge, and that is the issue concerning the definition.