Hello everyone, we are really at our wits' end by now and we haven't fully paid the construction company yet, but they are starting to threaten us. The house is now finished.
Our staircase was supposed to become the centerpiece. It is concreted and we had the covering done ourselves by a well-known carpenter.
I'll say – as a non-lawyer but with some experience in construction forums – that based on your story and pictures, a complaint about defects after completion does not seem appropriate or even justified, and I advise you to take the payment demands seriously. My impression is that they tried to integrate an architectural house highlight into a general contractor’s standardized house and at least took the detailed planning lightly.
Actually, according to the building plan, the staircase should have been concreted up to the upper floor. Unfortunately, the last step was "forgotten," and now our last step consists of concrete, Styrofoam, screed, and tile – with underfloor heating. The construction company says that was just the practice of the concreter and is fine. Since we wanted to do the stair covering ourselves, we have to make sure the finish looks nice. We absolutely cannot find any way to make this staircase finish remotely attractive, let alone stable.
Unfortunately, you haven’t shown the building plan here yet, so I can’t verify it. The detail of the exit step is already a classic example of miscommunication. There is no "right" here, only "your 'wrong'" or "my 'wrong'." Unfortunately, it won’t look nice either way, certainly not tiled, because the only suitable finish here would have been to choose a covering with the appropriate wood surface and execute the exit visually in the thickness of the step coverings.
Until proven otherwise, I suspect all errors lie with the client here.