NRW: Exemption procedure with minor deviation from the development plan

Doesn't contradict itself, does it?

The building boundary basically applies to exterior walls.

Not only. Baunutzungsverordnung, § 23 Überbaubare Grundstücksfläche ... (3) If a building boundary is set, buildings and building parts must not exceed it. A slight protrusion of building parts may be permitted.

It may also depend on the development plan.

Yes. Baunutzungsverordnung; § 23 Überbaubare Grundstücksfläche ... (2) ... Further exceptions of a certain type and extent may be provided in the development plan. But then these would be exceptions that would have to be applied for according to §31 Baugesetzbuch, so that a prerequisite for exemption from approval is not met and therefore an approval procedure must be carried out.

Not only. Baunutzungsverordnung, § 23 Überbaubare Grundstücksfläche ... (3) If a building boundary is set, buildings and building parts may not exceed it. A slight protrusion of building parts may be permitted.

Learned something new again. Thanks.

When I walk through the new development areas, many buildings stand directly on the 3m building boundary. The roof overhangs then protrude even further. Especially with today's narrow lots, this has quite a corresponding relevance. Up to what depth is a roof overhang considered a slight protrusion? That must be defined somewhere, right? I just can’t find any appropriate court rulings.

(2) ... The development plan may provide for further exceptions specified by type and scope. But then these would be exceptions that would have to be applied for under §31 of the Building Code, so that a prerequisite for exemption from approval is not met and an approval procedure must therefore be carried out.

So this is rather a hypothetical discussion: That would be illogical. If the development plan allowed an overstepping of the building boundary by, for example, 50 cm (possibly limited to a certain width) and I keep to this value with my house plan. Why should I then carry out an approval procedure? The purpose of the exemption procedure is that the architect declares that the rules of the development plan are being followed and therefore no approval procedure is needed.

So I am just interested. I do not want to question your statement.

(3) If a building boundary is set, buildings and building parts may not exceed it. A slight projection of building parts may be permitted.

Good morning, Which building parts are allowed to exceed the building boundary? Or is this something to be clarified in an approval process with the authority? I am specifically concerned about balconies. The state building code precisely regulates by how much they may project with regard to the clearance areas. Exceeding the building boundary is something different. Likewise, in Hesse, the size of roof overhangs is regulated with regard to the clearance areas. Best regards

That must be defined somewhere, right?

No, and precisely because 70 cm can be significant in one construction project but 1 m insignificant in another. Here are a few quotes:
BayBO implementation notes 2008:
A roof overhang is fundamentally irrelevant for setback distances whenever it is customary for the location or landscape. Regardless, the roof overhang must not have an independent function (e.g., covering a motor vehicle parking space).
Recommendation for building regulations NRW 2018:
A roof overhang must not have an independent function (e.g., covering a motor vehicle parking space), otherwise it loses its privilege according to paragraph 6.
Recommendation MV:
Protruding building parts have a structuring and design function. A roof overhang is not relevant for setback distances if it is characteristic of the local appearance. Regardless, a roof overhang must not have an independent function (for example, covering a parking space).
FAQ on the Hamburg Building Code:
Roof overhangs are disregarded when calculating setback distances if they exhibit the characteristic of subordination (§6 para. 6 no. 1 Hamburg Building Code). This is the case if the roof overhang is a maximum of 50 cm deep. Projecting rain gutters may be disregarded.
This concerns setback distances, i.e., building regulations law, hence state law. Furthermore, these are not laws or ordinances but recommendations from ministries to building authorities. Whether these regulations apply to the nationwide planning law, here the building boundaries described in the Land Use Ordinance, is decided by a court on a case-by-case basis under consideration of the very specific circumstances in dispute. Often, however, the court refers to state law.

If the development plan allowed an exceedance of the building boundary, e.g., by 50 cm

Here it depends on the precise wording. A common formulation would be, for example:
The building boundaries may exceptionally be exceeded by balconies, with the exceedance limited to half the building width and a maximum depth of 1.60 m.
If the word "exceptionally" were missing, it would indeed have to be discussed whether this then constituted an exception rule within the meaning of §23 Land Use Ordinance.

Which building parts are allowed to exceed the building boundary?

All, provided the exceedance is only minor. A quantification is not possible by law and must be decided on a case-by-case basis. Equally the assessment of whether the exceedance requires a dispensation according to §31 Building Code or not. Common practice is
- that a non-functional roof overhang of 50 cm is ignored. It only appears in the construction documents in the attic floor plan and elevations. It is not shown on the site plan, is not considered in setback distances, and not in the calculation of floor space ratio.
- that a 1.50 m projecting balcony does not trigger setback distances but requires a dispensation if it exceeds the building boundary and is included in the floor space ratio calculation.