Questions on the interpretation of § 34 Building Code

Who among them unsettled you like that? What kind of people were they? Architects? Civil engineers? House sellers?

No one in particular, and I don’t think you can really speak of being unsettled here but rather just real life. I always ask critically, want to understand and check for plausibility. And yes, all the people you mentioned were involved.

Who interpreted what in what way? What opinions were expressed?

Difficult to reproduce in detail. In the end, it was a mess that urgently needed to be sorted out. Everything was there:

[*]some called the paragraph a "rubber paragraph", somehow it would work out, but no one knew exactly how. Not very reassuring to me
[*]others saw a strict building line at the front, the rest didn’t matter
[*]someone else established a 1/3 rule; you can deviate 1/3 from neighboring buildings. To me, not understandable at all. 1/3 of what exactly? Unclear.
[*]no one spoke of the rear building boundary; I only learned about that here in the forum
[*]everyone agreed the roof shape was important. Now I have read a lot and found that roof shape and pitch obviously are not criteria
[*]it was similar with the plaster facade; but we want clinker brick; according to my research this should be possible
[*]and so on and so forth

Then it is his task to sell the desired plan as approvable with skilful wording as well.

That would be great. My expectation is: the planner is poorly informed, puts forward claims that are not true (see above), and we have to take care of it ourselves, meaning convince the planner. Added to that is an uncooperative authority. The responsible caseworker is anything but helpful and just grumpy and annoyed. I had called her before we bought the property to make sure it was building land. Even then there were discussions regarding § 34. The statements by the caseworker were inconsistent and not comprehensible. She couldn’t justify anything at all. My biggest concern, that the authority is poorly organized internally and therefore not transparent externally, was also confirmed. A little later I called again (still during the preparation of the purchase) and reached a very friendly employee on sick leave replacement who could not understand the statements of his colleague.

Well, and that’s how it comes that you have to take care of things yourself. I would have wished it to be different as well.

A general note, as we encountered a comparable situation during the house construction:

The responsible caseworker will eventually return from sick leave, so always remain polite in your tone – even if the decision-maker does not seem competent to you. Of course, you may fight for your goals in the matter.

If decision-authorized interfaces – possibly driven by stubbornness, wounded pride, or similar reasons – take a hard line, you will have to engage in an extremely unpleasant additional battle. Even if you do not succeed in the end or a supervisor can be involved, it may considerably delay your project and cost many nerves that you will better need later.

some called the paragraph a "rubber paragraph"

Yes, especially the consideration of the actual building boundaries gives this impression. Have you already found and read this ruling: VG Gelsenkirchen, decision of 02.11.2011 - 5 L 947/11

others saw a strict building line at the front

You can see it that way. Your bad luck is that the street distances of your neighbor houses hardly or not at all differ. IMHO, however, the small number of neighbors (3) speaks against deriving an actual building line from this. Ultimately, you are at the mercy of the ill-tempered caseworker, unless you can afford a court case in terms of time and money. The same goes for the draft designer; even if he is incompetent, nothing works without his signature.

someone else established a 1/3 rule; you can deviate 1/3 from the neighboring buildings.

Nonsense.

[*] everyone was of the opinion that the roof shape was important. Now I have read so much and found out that the roof shape and angle are obviously not criteria [*] it was similar with the plaster facade; we would like brickwork; according to my research that should be doable

Here the case law is clear: Without a design statute, the authority has no influence on these features. Only the building regulations emergency brake against disfigurement would remain, but the hurdles are very high.

On Wednesday we have an appointment with a new architect in the role of planner. Let's see how he evaluates it. If he makes a good impression and acts in our best interest, I would like to entrust him with the further implementation and not want to worry about it anymore. That would be the best case.

Otherwise, the next plan is a personal visit to the authority during office hours. I will definitely continue to report on how it went.

Because the building authority also refers to the existing situation. The shed was already far back. Exactly where you wanted to build... It doesn't have to be that way, but it could have been helpful. But never mind: life does not rage here in the forum, but outside.

Thank you also for your support. I have found an interesting document on the interpretation of § 34. It states: "The building plot itself also belongs to the immediate surroundings. The development realized on it, or that has been removed but still has effects, shapes the immediate surroundings."

VG Gelsenkirchen, decision of 02.11.2011 - 5 L 947/11

Very interesting... what I read there does not necessarily always make me happy. But at least it helps in assessing the situation. I still have a question: in this thread it was communicated that the area to the right (with development plan) must not be taken into account. Why actually not? One could consider the terraced house as a worthless outlier and include the houses to the right of it in the course of the blue line. Then we would have a building area that we would like very much.

In the above-mentioned decision I found, quote:
"The area of the property that may be built upon can be determined in a development plan pursuant to § 23 of the Land Use Ordinance (Baunutzungsverordnung) by building lines, building boundaries and building depths. The properties located in the unplanned inner area within the meaning of § 34 of the Building Code (Baugesetzbuch), which - undisputedly - also include the building plot of the joined party, are thereby equated with the qualified planned area with regard to buildability. In place of possible regulations of a development plan here comes the existing surrounding development, into which the project must fit according to § 34 para. 1 sentence 1 Baugesetzbuch in its character."

Is this now impermissible taken out of context, or could I also use it as an argument for us? So, to draw a factual building boundary into the development plan area, over the terraced house?