Carport on property boundary, treated the same as a garage?

Horrido,

I have been unpleasantly staring at the Landesbauordnung Rheinland-Pfalz as well as our development plan for a long time and have the following question:

§ 8 LBauO RLP
(9) Against property boundaries, without setback areas or with a smaller depth of the setback areas,
1. garages without fireplaces,
2. buildings and facilities for local supply with electricity, gas, and water, and
3. other buildings without living rooms and fireplaces
may be erected [...]. The buildings according to sentence 1 may not exceed a total length of 18 m at all property boundaries.

§ 62 LBauO RLP
(1) Notwithstanding any permission required under other regulations, the construction, installation, erection, attachment or alteration of the following structural facilities, other facilities and installations do not require a building permit:
1. Buildings
[...]
f) Garages, covered parking spaces and parking spaces for bicycles up to 50 m² floor area and an average wall height of the exterior walls of no more than 3.20 m each, with walls with gables a ridge height of no more than 4 m; excluded are garages, covered parking spaces and parking spaces for bicycles in the open countryside as well as in the vicinity of cultural and natural monuments
[...]

Therefore, I would subsume a carport under the category "buildings." We have now planned a 10 m long garage on one property boundary and would like to set up a carport at another property boundary or directly at the front on the street – in the respective corner of the property there. Two sides of the carport would then be on the boundary. If we assume 5 x 5 m for the carport, we would have 20 m of development on all property boundaries combined.

Do I understand correctly that
a) a carport is a building according to the LBauO, and
b) its length on the property boundary is therefore also subject to the mentioned 18 m limit?

Then I would have to reduce both parking spaces to the common 18 m.

You have understood that correctly according to my understanding. So yes!

Do I understand correctly that
a) a carport is a building according to the state building code

No, a carport should not be considered a building in your area either, but an ancillary structure/building structure.

whose length on the property boundary is therefore also subject to the mentioned 18 m limit?

That, however. Boundary development concerns all ancillary structures (a garage is also an ancillary structure).
But: boundary development does not occur at the street, as it concerns the neighbor boundaries.

Now a look into your GarStellVO:
it could also be that you have an open garage. Garages are parking spaces. Building structures are also mentioned.
But regardless, it remains the same: they trigger setback areas.
However, according to the GarStellVO, 3 meters access and driveway must exist between “open garages” and the street.

By the way: Par 8, Abs. 9, b, 12 meters on a neighbor boundary, of a total 18 meters

Par 62 regulates building projects exempt from approval and has nothing to do with your question, since “exempt from approval” only concerns the administrative process, but does not override requirements and laws.

According to the state building code and GarStellVO RLP, a carport would actually be considered a garage because it is partially enclosed (on top and possibly on the side) and is not a "bare" parking space:

§ 2 Landesbauordnung RLP
(8) Parking spaces are areas for parking motor vehicles outside public traffic areas. Garages are fully or partially enclosed rooms for parking motor vehicles. Exhibition, sales, workshop, and storage rooms are not considered garages.

§ 2 GarStellVO RLP
(2) Open small garages are garages that have non-lockable openings leading directly to the outside, totaling at least one-third of the total area of the enclosing walls.

Actually, according to § 3 GarStellVO RLP, I should also maintain a distance of 3 m from the street in front of the carport, although I currently have doubts about the scope of GarStellVO based on § 1 GarStellVO in conjunction with §§ 2 (8) and 47 of the state building code, since according to the text it only deals with the required parking spaces of the building (and these are already covered by the garage and the parking space in front). ChatGPT says it generally applies to all garages and parking spaces, but AI also likes to hallucinate sometimes :D

I actually like laws quite a bit, but here I’ll just ask the building authority.

According to the state building code and GarStellVO RLP, a carport would actually even be a garage,

maintain a distance of 3 m from the street,

I wrote that, yes. Ultimately, you also have to look at the development plan to see if there are any further permissions or restrictions.

A building preliminary inquiry is more reasonable than asking the building authority. You won’t get a binding answer there anyway.