The construction company is building a basement smaller than in the factory plan

My question in the thread about concrete coverage was of a technical nature: which variant of the renovation should be preferred. The answers went in a different direction.

The reason the answers went in a different direction was probably also because you had to be coaxed bit by bit to get the information out of you. Accordingly, the posts in your thread became more direct shortly thereafter. But let's just leave it at that here.

The expert did not provide any written evaluations, but stated that the basement can be renovated and that the structural builder should do it. A suitable variant should be agreed upon. The basement can be made suitable. But a black tank is simply inferior to the ordered white tank (not as durable, etc.). And it is smaller than ordered. In addition, the wall to the neighbor cannot be inspected from the outside (cannot be renovated from the outside).

No, you should not agree on one variant here, but you should set the tone and specify exactly what is to be done now. I am not a lawyer but I see it this way: The contractor basically has the right to fix defects first. Here, however, he cannot just push the reinforcement deeper into the concrete. Thus, you are faced with a correction that will deviate from the agreed quality. Since you theoretically do not have to accept this and could insist on contract fulfillment, you are now in control. Your contractor will try to talk you into the cheapest solution technically. Exactly for this reason, another expert to be commissioned by you comes into play here, who will present the best solution to you. This expert will then also evaluate the remaining defects technically and professionally so that, with this information, a lawyer can consider possible compensation payments. You will either demand far too little or far too much from your contractor with corresponding consequences.

I want to try to settle this with the structural builder without an expert. Is the burden of proof on him if I officially complain about something in writing? Or can he simply reply "no, the measurements are correct"? I want him to bear the costs for the evidence himself.

That is a big mistake you are making. The contractor first lied to you and denied everything. Do you seriously believe he sees you as an equal in these discussions? He has been in the business for years and can tell exactly when a client is "insecure." If you inform him that the structural shell deviates by 6 cm, he will of course first check what is going on. If he comes to a different conclusion than you (whether that is actually true or not is another matter), he will inform you accordingly and you will be back at the start. So yes, he could simply reply like that, maybe just to gain time. The "costs for the evidence" that he does not want to accept will then also be included by your lawyer in the demand letter. Why should you be left with that? After a car accident for which you are not at fault, who pays for the expert and lawyer costs? Of course, the party causing the accident. That means you do not even have to inform him in advance that you intend to pass these costs on.

In your case, you can actually only win with an expert and lawyer if what you have found is true.

The recommendation regarding the insurance will be added.

You can save yourself that, because construction defects in self-performed trades are not insurable. Otherwise, any construction company could "botch" as they please and then bill the insurance afterwards. Their business liability insurance would apply if they caused damage to other trades, but not to their own work.

That’s what my expert told me.

One more addition on how to determine the amount of damage: 1. Assessment of the financial loss through the financial statement 2. Assessment of the financial loss based on the contract price 3. Assessment of the financial loss based on the actual cost of remedying the defects

Take a look, when you have the chance, at the BGH ruling from 27.03.2003 - VII ZR 443/01 -, BGHZ 152, 301-305. The reasoning of the judgment is really interesting and might answer some of your questions. But your case, for example, could already be completely different due to a small deviation. In the construction industry, there are basically no precedent rulings that can be transferred 1:1 to other construction projects.

How should answers to these questions help with my problem? I honestly can’t see it. That’s why I ignore them.

A forum is about give and take. If you want a one-sided question-and-answer game, then hire someone who provides their time in that context.

It helps in identifying causes. Things don’t just happen randomly. Bad luck in construction can happen to anyone, but if patterns emerge, you have to do something about it. You are still at the beginning of the construction phase, so something can still be done. But if you want to exclude yourself from the equation, fine, but then...

My question in the thread about concrete cover was technical in nature: which variant of the repair should be preferred. The answers went in a different direction.

...Don’t try to scrounge expert knowledge here.

Hello -
exciting story - what happened next?