Berlin front structure for securing the excavation pit

So, I also don't like the slope to number 18, or rather it shouldn't stay like that.

The slope to the garage currently looks uncritical.
Am I correct in assuming that the new building will have a basement? That means the pit still needs to be expanded?

In general, you can calculate for yourself where you will need a retention system. Outer edge of the foundation slab + 1 m working space, and then slope off at 60 degrees. At the top, at least 1 m of soil should remain. If that doesn't fit, then a retention system is necessary.
Based on the site plan, I think it will be tight towards the street in the west and towards house number 18.

I don't believe this was done. I asked the architect and the general contractor once at the beginning, but the architect said it was not necessary at that time, and I failed to check it again

An expert report on a building site that will then turn into an excavation would indeed have been of extremely limited usefulness, but securing the adjacent neighboring house would still have high priority.

Yes, unfortunately I don’t have a plan for the excavation pit. The shoring is also not planned yet. I’m still waiting for that to be done. [...] The plan was to complete the excavation pit together with the demolition of the old house with cellar without any waiting time. Due to poor planning (or completely missing planning), it turned out during execution that some additional measures had to be carried out that were not planned, so the excavation was stopped in the middle of the work.

It is still not even clear to me for five pfennigs whether the excavation pit is now also supposed to be extended in order to place a new cellar in the new location under the semi-detached house, or whether the condition is only to remain as a reminder of your shrugging shoulders. Every child knows (although apparently not every construction contractor actor) that lack of planning leads to surprises as surely as Amen in church. Are you even aware that you are fully liable with all persons involved, including criminally, for every (non-)action of your incompetents?

Sorry, that’s my mistake. I didn’t understand why "guarantee" was mentioned here, then I realized that I had mistakenly used it in my first post, while I meant "bond"—i.e., the Berlin shoring system

*eye rolling* *still don’t understand* what Friedrich Schiller has to do with all this nonsense is beyond me. I assumed that you, among other things, had provided a deposit for possible damages to the sidewalk.

So I don’t like the embankment to number 18 either, or rather it shouldn’t stay like that.

I didn’t like it either, but GU now says that we have a written confirmation from the municipality that the current situation is not dangerous.

Am I correct in assuming that the new building will have a basement? That means the pit needs to be expanded?

It has still not become even remotely clear to me whether the excavation pit is to be extended to place a new basement in the new position beneath the semi-detached house.

Yes, we will have a basement. The excavation pit will be expanded so that it corresponds to the dimensions of the house + 1 m (i.e. it will be 12 * 15) and 3 m deep.
We will hopefully start with the Berlin substructure next week.

Based on the site plan, I think it will be tight to the street in the west and to house no. 18.

Exactly, it is very tight from east and west, but according to the soil report we have to make the Berlin substructure all around the complete basement. So it will be done on the north side (i.e. on the garage side) and also in the south on the crane side.

That is supposed to start next week and you don’t even have a cost estimate for it? A complete shoring of the excavation pit is not a small undertaking, but can be quite expensive.

Just an update here: It took some time until it was finally finished. The experts said we only need it from 2 sides [Straßenseiten]. It cost about 35K. Now the construction pit is finished and the work in the basement begins. Thank you for your advice.

Interesting, how many meters is that approximately that had to be secured? Probably about 1300 euros per meter, right?