Berlin front structure for securing the excavation pit

A friend and I are planning a new semi-detached house in place of an old single-family house. We have already completed the planning and received the building permit.

Hello everyone,

There are several problems with the excavation pit in our construction project.

I agree with that.

The general contractor says the planned house is big (2 semi-detached houses, each 11*7) So that is 11*14 m

which is rather normal, not big. My single-family house is 10 * 15 m

and the plot is small (~450 m2), which brings some technical difficulties.

That is nothing special. Show us a plan of the excavation pit on the plot.

The bad thing is that we discover all these problems only step by step and not as expected in the original planning:

That is really bad. What does your site management say about it?

1) First, it turned out that the edges of the excavation pit are weak and we need a support for the crane, which is why a crane foundation was built.

The contractor only realizes that after the basement is gone?

2) Secondly, it was found that the plot is still too small for the crane, and a permit was needed to set up the crane (partially) on the sidewalk.

Ditto. That is the consequence of lack of planning.

The first two steps were completed by the end of June, and then the work was completely stopped (except for the crane setup).

Leaving an excavation pit open longer is counterproductive.

At the end of August, my new neighbors contacted me and were concerned because they see that the sides of the pit are slipping more and more, so the pit is rising toward their property and the stability of the slope is no longer guaranteed.

As a neighbor, I wouldn’t have waited that long. As the builder, even less so.

At this point, the general contractor said that they have already discussed this problem with various authorities. They proposed to increase the slope of the pit, but this proposal was rejected because it would affect the sidewalk.

That sounds logical.

The only remaining solution was then to provide a bond to maintain the durability of the walkway.

That is nonsense. The bond merely transfers the risks to you (your contractor).

After an additional geotechnical investigation, it was found that a sheet piling is required on all sides and not just on the sidewalk.

That can quite well be. So what now, Berliner Schutzverbau or sheet piling?

My questions are:
Does all this make sense?

With so little information, that cannot be assessed.

Does it make sense to find out these problems so late? Does it really take about 3 months to reach this result? Should I hold the general contractor accountable for these delays?

The building ground belongs to the builder. Who is responsible for the planning errors cannot be judged based on the information provided here.

Note: At the end of June, I agreed with the general contractor that the house should be completed by the end of February 24, as our contract states: "The contractor undertakes to complete the contract object ready for occupancy within 8 months from excavation of the construction pit, provided weather permits."

In my opinion, the construction period can no longer be met. Whether the contractor is responsible for this, a specialist lawyer will tell you.


Finally, how much time should I expect to finish this Berliner Schutzverbau and finally start building?

That is hard to say. First, the whole thing must be planned and approved by the structural engineer.

I read online that costs could be several tens of thousands, is that realistic?

The contractor will tell you. In my opinion, sheet piling is more expensive than Berliner Schutzverbau. The basis here is a sound plan.

20-50k is possible.

Thank you very much

You’re welcome.
Best regards

The distances to the neighbors actually still look quite good.

That is really bad. What does your site management say about it?

The contractor only realizes that when the basement is gone?

That is nonsense. The guarantee only transfers the risks to you (your contractor).