Botch on the interior staircase or do I have to accept it like this?

Yes, honestly, the staircase as a lightweight staircase should have been installed completely after the tiling work. That's how it was for me. He probably just had time and wanted to get the job done. It looks like a standard GU/GÜ staircase. The staircase builder of my GÜ would probably have done it similarly. Since the desired patterns were about twice as expensive there, I had the service removed. Then I found a pretty good staircase builder from Poland with a sales office in Berlin. Sorry that things are going so badly for you now. I fear you can hardly claim any real workmanship defects. You should talk to the tiler to see if he can basically lay under the posts or rather around them.

Originally, "the architect" planned stringer stairs with tread and riser steps. There was no visualization or anything like that.

During the sampling, the stair builder convinced us to rather take a bolt stair, as it looks lighter in the small stairwell and would even be cheaper. So we found a model that pleases us visually, with a handrail without posts, and sampled it for the EG-OG staircase. For the stairway to the basement, we still wanted to keep a stair with tread and riser steps to possibly store something under the basement stairs without all the dirt falling down.

Our question was explicitly whether the same handrail from the EG-OG staircase could also be installed for the KG-EG staircase so that we would have a uniform appearance and no posts (annoying when cleaning, appearance, etc.). That was promised to us. After that, the materials were sampled.

After months of waiting, the additional agreement of the general contractor (probably the stair builder had already forgotten everything again by the time of the offer preparation) arrived. Here I actually did not read closely, because the offer states: Stair system KG-EG-DG Entrance and exit posts 80x80mm handrail HL1, approx. 12x4cm Load-bearing bolt stair EG-OG: Entrance and exit posts PS (no measurements) Handrail BTB (no measurements)

I do not know what the abbreviations stand for, since I am not a stair builder either. My wife and I naturally assumed naively that this corresponds to the sampling.

There was no sampling protocol, but I believe this is actually a contractual requirement according to the general contractor’s construction contract to make samplings and changes effective. Whether the sampling is therefore even "valid," I can't say, maybe yes but maybe not, to my advantage.

Furthermore, the additional agreement only mentions 2 posts exclusively, namely only at the entrance and exit. Also, regarding the one handrail it states 12x4, but it is actually 10x4. Even if they now want to behave unfairly and say that I signed it like this and "a contract is a contract," I have at most commissioned 2 posts and not all the others. Moreover, if “a contract is a contract,” the size of the handrail would be wrong and not according to the additional agreement.

For details not listed in the additional agreement regarding, for example, the parapet construction, there is only he-said-she-said, i.e., 2 statements (my wife and I) vs. 1 statement (stair builder).

Against this background, I am trying to assess what I can demand. Fortunately, the money is with me, and there is no leverage on the general contractor’s side in the sense of a construction stop until payment, as the inside stairs (and outside stairs) were the last obstacles for moving into the house. Everything else is done.

I am not trying to force anyone to perform services that were not agreed upon or to say afterward, "no, but this doesn't look good, we want something else after all." The "German master stair builder" not only shoved a stair system into the house (sorry for the word), but also did not install what was sampled.

Any opinions and assessments regarding the new details?

Haven't you already taken out a final installment guarantee, as is common and required with many general contractors [GU]?

It could have been tiled for two months already...

(Including scheduling) planning assumed, but here it seems to be generally in short supply :-(

For me, it now seems that he talked us into something that reduces the work for him but significantly increases the effort for all subsequent work, which was not clear to me at all.

This phenomenon has a technical term: "regie hours," and regularly causes major budget overruns. Planning is (roughly, without guarantee of limitation) twice as expensive if omitted. Poor planning >> 10% more expensive house, grossly inadequate planning >> 20% more expensive house (scale open upwards).

Didn't you already take out a final installment guarantee, as is common and required by many general contractors?

Yes, I did. Why is that an issue? Would you be so kind as to answer my other questions to you?

What does this practically mean for me now? I didn’t ask about the advantages of proper planning, but rather have a specific concern and request concrete assistance for an urgent problem right now and how you would tackle this to get the best possible outcome and on which arguments you would base the corresponding approach.

Please be concrete here, 11ant, because that would really help me.