Plot with terrain drop - separating wall neighbors - foundation?

Just let him read along here. Otherwise, his "Leaning Garage of Pisa" will soon convince him :-(

Unfortunately, he doesn't speak German that fluently. The house/garage is self-built (I have huge respect for that), but the designs come from a planning office.

Professionally, I was advised as follows: Tear down the wall Then dig down about 1.5m starting from my terrain Insert hefty L-profile parts across the entire width with 200m height Cost: 10k

The problem is the development plan, which allows a massive intervention in the height level. There is a slope, and every builder violates their driveway.
Well, that doesn't help you either.

I have to admit that I find your contributions contradictory.
Your drawing apparently only shows the target state, not the actual state.
Isn't there a regulation to adapt to what already exists? Not to damage one's foundation with one's own construction? I understand it at least as he now correctly constructs his foundation, but you want to excavate because you think you are entitled to it. Or am I misunderstanding?

Regards, Yvonne

Hi Yvonne,

no, there is no such regulation, it is not possible anyway on a street with a slope.
The sketch does indeed show the target condition. Currently, due to the excavation of the basement at the property boundary, there is still about 70cm of soil lying around. That will of course be removed again, otherwise I would have a hill in front of the patio door instead of a garden.

Here is a somewhat more detailed sketch:

Can you remove your pile of dirt there with relatively little work (maybe an excavator on-site)? That should actually open everyone's eyes.

Is the garage already standing?

The problem, in my amateurish opinion, lies somewhere else entirely and is much more threatening. The border-adjacent foundation of the garage should have been planned completely differently from the start. Then you basically wouldn't have the problem at all.

The border-adjacent foundation of the garage should have been planned completely differently from the start.

I really hope that the principle drawing is incomplete at this point. If the garage in this location seriously only has strip foundations, I soon see it "standing" on a slope.

The tenor is that it will collapse soon.
So what is the concrete advice to the OP? What can he do?
Go straight to the authorities and tattle?