Terrain modeling different from the building application - allowed? (NRW)

Well, this is exactly where the interpretation of the regulations begins. For NRW, it is additionally complicated by the fact that the new state building code has been in effect since the day before yesterday. And it is phrased differently again. Since you have a building permit according to the old state building code, we will initially stick to that: According to §2 (1) 1., any embankment is considered a structural facility. According to §65 42., an independent embankment up to 2.0m is exempt from approval. Accordingly, a dependent embankment, which IMHO is present here since it is to be carried out in temporal and spatial connection with the construction of a single-family house, would not be exempt from approval. According to §6 (10) 2., it would, however, be relevant for setback distances regardless of whether approval is required or not. Now the overburdened employee of the building authority, who considers this change insignificant and does not want to have the case back on their desk, could argue that the embankment is independent because it has no influence on the construction of the building and the terrace, so one can build as approved, completely independent of whether embankment is added or not. But if it is independent of approval, the extension of the embankment would have to be assessed according to the new state building code. And according to that, its ground area should not exceed 30m² to be approval-exempt.

Okay, hm.... quite complicated.

As far as I understand, independent fillings are:

[...] all artificial changes to the surface either by raising the ground level (filling) or by deepening it (excavation).

Furthermore, it is restricted:

Independent fillings and excavations are those that have their own function and purpose and are not just, like the foundation pit of a new building, parts of an overall project.

And finally the note:

Only those fillings and excavations are covered by the exemption from approval that are not related to (other) structural measures, such as excavations at a basement level. A noise protection berm or an earth berm carrying a noise protection wall is not a filling, but an independent structural facility.

If I now summarize this, one could understand that we have received approval for a certain filling that is definitely DIRECTLY related to our construction project. The direct connection is at least given by the fact that our terrace requires this filling to have a level surface.

However, if more earth is added now, then this is no longer DIRECTLY related to the rest of the construction project.....right?

If you now add more soil, this is no longer DIRECTLY related to the rest of the construction project.....or is it?

That would be the opinion of my imaginary overwhelmed caseworker from #13. My view is that, since the construction project has not yet been realized, the soil filling is indeed directly related to the house and the terrace. Hence my recommendation in #11 to consult the architect you trust. He knows your construction project and ideally also the people at the building authority. Who is supposed to manage the construction site for you? You can also ask him for his assessment. Didn't you have the plot with the 5m height difference to the street? Has the development plan been relaxed or is the municipality itself carrying out massive earthworks in the building area? Compared to that, your change would just be a molehill. Still, I wouldn't do it without asking the building authority first, but I consider another approach justifiable.

Yes, you are of course right, the architect will be contacted this week. However, we have lost some trust in her in the past. Too many mistakes had crept in across too many areas :-/ Nevertheless: asking doesn’t cost anything.

Hattest Du nicht das Grundstück mit den 5m Höhenunterschied zur Straße? Wurde der Bebauungsplan entschärft oder veranlasst die Gemeinde selber gigantische Erdbewegungen in dem Baugebiet?

Yes, indeed, that is exactly our building site. It turned out that the elevation levels in the development plan were simply wrong and still are in the current plan. The street heights do not match the terrain heights but at least now the slope is registered as it really is on site. Our plot is now about 70 to 90 cm higher than the street.

I took the liberty of overlaying your sketch and your avatar transparently. You are discussing a design detail here where every raised bed or children's sandbox would have greater relevance. If one had to make such a fuss every time about such a minimal terrain modeling, landscape gardeners wouldn't need to start with anything anymore.

I took the liberty of overlaying your sketch and your avatar transparently.

Haha, thank you! That actually matches quite well
Attached is a larger section for better illustration