Plot with terrain drop - separating wall neighbors - foundation?

Talk to the neighbor, get a structural engineer, and if that doesn't work, go to the building authority.

The general consensus is that it will collapse soon. So what is the concrete advice for the original poster? What can he do? Go straight to the authorities and snitch?

As far as the garage is concerned, I assume that it has been approved, constructed accordingly, and additionally equipped with pile foundations in this location. I suspect the wall is an illegal construction from the official standpoint. If the garage is stable, the wall will ultimately be stable as well – unless frost damage occurs on the foundation. If the garage is not stable, the ground where it "stands free" will give way and the wall will tilt. How dramatic this is will depend again on the soil conditions, precipitation, and frost. It could be that frost destroys the foundation and the wall slips away. It could also be that it tilts at the top edge by four centimeters over twenty years. However, if the original poster now underpins the foundation or drives piles in front of the wall, it could also be damaged, and then he will be the villain. Sloping the foundation on his side (possibly with an insulating layer in front) would be one approach.

Now I understand it
In order for him to understand it too, you would probably have to move the provisionally stored pile of earth aside.
Warn your children about this area and then take another look at the wall together – hoping that it doesn’t collapse immediately.

Best regards in brief

Can you remove your pile of earth there with relatively little work (maybe an excavator on site)? That should actually open everyone's eyes.
Is the garage already built?

Everything is already there.

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

I only saw it "from the outside," but that's how it looks to me.

The general tone is that it will collapse soon.
So what is the concrete advice to the OP? What can he do?
Go directly to the authorities and snitch?

I would rather not snitch – it is very important to me to resolve this properly now.

Talk to the neighbor, get a structural engineer, and if that doesn’t help, go to the building authority.

Thanks for the tip!

Regarding the garage, I assume it is approved, also executed accordingly, and in this location additionally has piled foundations. I suspect the wall is an illegal construction from an official point of view. If the garage is stable, the wall will ultimately be stable too – unless frost damage occurs to the foundation. If the garage is not stable, the ground where it “stands free” will give way and the wall will lean. How dramatic this is depends again on the soil conditions, precipitation, and frost. Frost could destroy the foundation and the wall could slide off. It could also lean by about four centimeters at the top edge in twenty years.

But if the OP now underpins the foundation or drives piles in front of the wall, it could also be damaged and then he would be the bad guy.

The building application was submitted as a free-standing structure and was approved as such. I do not really want to build any posts on my side now to support the neighbor’s garage. It’s really not my job. And I am also somewhat concerned about the risk.

Now I understand it.
To make him understand, you’d probably have to move the provisionally stored pile of earth aside.
Warn your children about this area and then take another look at the wall together – hoping it doesn’t immediately topple over.

Best regards in short

At the moment, I don’t even want to touch my earth with a pair of pincers. The foundation was poured without formwork, at least half of the concrete at the top edge is on my property, and if I hit it with an excavator I might pull the whole wall down at worst.
Our construction company has also already announced that they will approach the wall to a maximum of 1.5 meters.

The building application was submitted as an exemption and was approved as such.

This also happens with plans that must be adhered to. Less foundation than in the plan means an illegal construction - what was approved was something else.

And here too, I have some concern about the risk.

Exactly, your jackhammer could crumble more than the frost

Do you possibly speak another common language better than German, e.g. sports or music or the like, so that after the eighth round of drinks he understood what you meant?

This also happens with plans that must be followed. Less foundation than in the plan equals illegal construction – something else was approved. Exactly, your jackhammer might crumble more b-b-b-b-than frost

In the submitted plan, a foundation of 110cm was planned for the garage, about 30cm of which lies below ground level. To the left, towards me, the rest of the garage foundation is exposed. The plan comes from an architectural firm. I somehow have the impression that they are not aware that there is no soil next to the foundation at all. In my opinion, the garage is also built about 60cm too high. But well.

Do you possibly speak another common language better than German, e.g. sports or music or something like that, so that after the eighth Herrengedeck he understood what you meant?

That’s an interesting approach! I will check on this.