Berlin front structure for securing the excavation pit

The general contractor has covered one side of the excavation pit so far, I’m not sure if that is really useful.

For that one side, yes, albeit moderately. Pun intended: overall, it remains a half measure.

She just says that the property is very difficult and something like: "Who could have known all these problems from the start"!

What does the site manager do professionally?

She only says that the plot is very difficult and something like: "Who could have known all these problems from the beginning"!

After an additional geotechnical investigation

Was there already a soil report before? Was one requested by the general contractor before the demolition?
How did it go for the neighbor? Did he have one? Was it communicated?

The work on the excavation pit began with the demolition of the old house, as it already had a basement.

Did the basement have to be removed? Could it not have been left standing?

In my humble opinion, the GC (general contractor) or the general contracting company should have known beforehand what they were about to build on. However, a soil report is the owner's obligation to provide.
You are the owners, right? Or did you buy the house including the plot from the developer?
The 8 months will be very tight. Do not make the mistake out of self-interest and put pressure - do not terminate the apartment yet.

I only see information from the soil survey here. No planned excavation pit. No shoring (sheet piling) planned either.

That is not quite clear. What do you think should have been done in this case?
The municipality also closed the streets (completely or partially) because the stability of the street is no longer guaranteed (at least that is their position).

Why? It should be clear to everyone that a guarantee does not solve the problem. It should also be clear to your site manager and you by now that the unshored excavation pit can and will affect the street. The costs of the remediation are borne by the party responsible.

It would have helped if the problem had been solved quickly here.

When I check again, the excavation pit seems to have exposed the neighbor's foundation to the east (seems to have no basement).

This is a 2-story house on a slab foundation, the slab is already suspended in the area of the foil stuffed underneath.
The exterior walls stand on it and load the slab in bending.
There is imminent danger, risk of the house collapsing :eek:

My summary of what I understood is five letters long: "nothing" (and even then I am not entirely sure).

The original poster and his building partner have thus received a building permit here, which I already do not understand: the cadastral excerpt shows the neighboring house no. 18 on 367/21 and the predecessor building on the original poster's property in a location that would suggest a boundary setback from the previous property owner. So I do not even follow the simple boundary distance to the neighbor here. Then I read about a basement of the existing building, which I do not recall being mentioned in the original poster’s previous thread - thus for me unexpectedly of a deep demolition. Here I see a "construction pit" like for a basement of the semi-detached house: the slope seems to contain a working space that would seem too generously dimensioned to me just for a deep demolition. Not that I had assumed the predecessor building had no basement - but I did for the new building. So I had certainly expected a deep demolition instead of just filling the existing basement, which of course would have been secured with sheet piling or similar to prevent an unwanted formation of a working space between the deep demolition and the neighbor’s boundary. I am surprised that I, as a building consultant (specialist, but from this perspective a theoretician), am thinking further here than a building contractor (for whom this should be an ingrained daily practice). Furthermore, I am then surprised that this "construction pit" might actually be a construction pit (for the new basement), because otherwise it could and should have been immediately / virtually simultaneously filled and compacted.

I therefore assume a planning unfortunately without an architect: i.e. it is apparently that a general contractor was engaged who then planned the still-built property virtually like a plane, detached from reality. If I were at the building authority, I would at least have conditioned the building permit on the submission of a demolition schedule. This looks to me like such a textbook farce that I harbor an initial suspicion that the mayor of might have found a new field of activity here. Ceterum censeo, the tax rate on thoughtlessness urgently needs to be increased.

Was there a soil survey before? Did the GC require one before demolition?

I don’t think this was done. I asked the architect and GC once at the beginning, but the architect said it was not necessary at that time, and I failed to check again :(.

Did the basement have to be removed? Couldn’t it have been kept?

Yes, it is at a different location and has a different size.

You are the builders, right?

Yes

The 8 months will be very tight. Do yourself a favor and don’t make the mistake of putting pressure on – don’t terminate the apartment yet.

From other threads I understood that 8 months are normal if the work starts under good weather conditions. I was mainly worried that it might be too late to start the work because winter is coming. I am not sure when I should start counting the 8 months.

I only see information from the soil report here. No planned excavation pit. Also no retaining structure (sheet piling) planned.

Yes, unfortunately I don’t have a plan for the excavation pit. The retaining structure is also not planned yet. I am still waiting for that to be done.

Why? It should be clear to everyone that one guarantee does not solve the problem. Your site manager and you should by now also be aware that an unsupported excavation pit can affect the street. The costs of repair are borne by whoever causes the damage.

Sorry, that’s my mistake. I didn’t understand why “guarantee” was mentioned here, then I realized that I mistakenly used it in my first post while I meant “retaining structure” – that is the Berlin sheet piling :rolleyes:

This is a two-story house on a ground slab, the slab is already suspended in the area of the foil underneath. The outer walls stand on it and load the slab in bending.

I am not sure how high the load is here since it is a very old prefab house, but it definitely seems dangerous. I also reported this problem to the GC, but it’s strange that this neighbor has not complained yet!

My summary of what I understood is five letters short: “nothing” (and even there I am not quite sure). The OP and his co-builder obtained a building permit here, which I already do not understand: the land registry excerpt shows the neighboring house No. 18 on 367/21 and the predecessor building on the OP’s property in a position that would allow assuming a setback waiver by the previous owner. So I don’t even follow the simple boundary distance to the neighbor here. Then I read here about a basement of the existing building, which I don’t recall being mentioned in the OP’s previous thread – so it’s unexpected to me to have a deep demolition. Then I see here an “excavation pit” as for a basement of the duplex: the slope seems to contain a working space that seems overly generous to me just for a deep demolition. Not that I had assumed the predecessor building to be basement-less – but I had for the new building. So I had indeed expected a deep demolition rather than just backfilling the existing basement, but of course then secured with sheet piling or similar to prevent unwanted formation of a working space between the deep demolition and the neighboring boundary. I find it strange that I as a construction consultant (by profession but theoretically seen) think further here than a construction contractor (for whom this should be everyday practice). Furthermore, I am then surprised that this “excavation pit” might actually be a construction pit (for the new basement), because otherwise it would have had to be immediately / almost simultaneously backfilled and compacted. So I assume a regrettably architect-less planning here: that is, a general contractor was apparently engaged who virtually overplanned the still-built property unrealistically like a planum. If I sat at the building authority, I would have at least conditioned the building permit on submission of a demolition schedule. This looks to me like such a textbook foolishness that I suspect the mayor of @goalkeeper might have found a new field of activity here. Ceterum censeo, the tax rate on thoughtlessness must urgently be increased.

The plan was to complete the excavation pit together with the demolition of the old house with basement without waiting time. Due to poor planning (or completely missing planning), it became apparent during execution that some additional measures had to be taken that were not planned, so the excavation was stopped in the middle of the work.