GU is building without a final factory plan

In the wording

the work and detail planning required for him

the work and detail plans to be created at all are already subject to the condition that the contractor considers them necessary for the execution of his contract. If he thinks that, apart from formwork and reinforcement plans, nothing else is needed and the installers can be allowed to follow their usual habits, then that is just how it is. Then only the set of plans from the building permit is the "bible" for the construction workers. I do not see any entitlement to drawings for your family album derivable here. Forcing such drawings by withholding payments despite defect-free performance results would be, from my point of view, a breach of contract on your part.

The contractor produces at his own expense

means nothing more than that he – insofar as he considers detail drawings necessary at all – produces them without additional charges. They do not become an assured inclusive service by that.

He is free to manage his people with any combination of drawings and verbal agreements about where to deviate from the drawings.

Thank you, that is indeed an interesting aspect that I had not seen before.

However, I also have obligations (approval of the detailed plans) which I simply cannot fulfill if there is an error in the detailed plans. If the plans are not detailed enough, that is one thing (as a layperson, I don’t really know what should be included and what not). But if there is an error, for example, the position of a door is incorrect, I cannot just sign off on that and trust that it will later be resolved through verbal agreements with the contractor (although it seems like that is currently how it works).

To give a bit more information. We also have the following in the construction contract:

The building must be completed no later than 17 months after
• handover of the planning documents, in particular the building permit,
• approval of the detailed plans by the client, and
• a written bank confirmation by the client regarding the financing guarantee of the entire construction project

To me, it seems as if the general contractor is holding back the final detailed plans so that we cannot approve them and the 17-month period does not start running. Now, it is fairly irrelevant to us when the house is completed. I rather think that the general contractor is interested in a quick completion (rising raw material prices). I am trying to find out if we have any other disadvantages because the detailed plans are not final and approved.

Gracious goddess. Would you perhaps like to stop the Earth's rotation until you have certainly counted every single one of the (roughly estimated several trillion) peas in the world? - currently a war is underway, and the preppers might be hoarding not only spaghetti and toilet paper but also taking some peas away from your count!

I can't just [...] trust that this will be settled later through verbal agreements with the craftsman (although it appears that this is exactly how it works at the moment)

Well then, I guess so after all.

For me it seems as if the general contractor doesn't hand over the final work plans so that we can't approve them and the 17-month deadline starts to run.

Obviously your "missing" Friedrich-Wilhelm hasn't stopped anyone from starting contract fulfillment (a lawyer calls this a healed defect). And this was done according to the result – what more could one want?

Are you a Roman (because according to Asterix they are responsible for spinning, *LOL*)?

But if there is a mistake, for example, the position of a door is incorrect

Your general contractor will build the house according to the approved plans. If you want a door located differently, that would theoretically have to be coordinated with the building authority first (but judging by your GC, he will probably do it "on the sly" as you want). Whether someone paints you an extra little picture with a laughing yellow sun on top and "for Dad" written on the back is practically unnecessary nitpicking. If the lady of my heart knew that, she would laugh and say you are just as quirky a bird as I am :)

Phew, this somehow took a strange turn. My question was actually asked neutrally. Why is the discussion now being ruined with sarcasm and irony? It reminds me of the internet of the 90s.

Still, thanks for the input...

Phew, this somehow took a strange turn. My question was actually posed neutrally. Why is the discussion now being rendered unusable with sarcasm and irony?

No, the humor is already in the initial situation. You share the self-perception of being objective with other pessimists. Let me tell you—in a forum with some accumulated construction experience—that your situation is mislabelled as a "problem." For you, construction is proceeding in accordance with what was commissioned; only the plans deviate (but as you yourself have noted, no one implements those errors). On tens of thousands of other construction sites, it’s exactly the opposite—sometimes dramatically so. Don’t become an alcoholic from the many bottles of champagne that you would actually have to pop here in solidarity with these other clients!

I never said that the initial situation was a problem, but that was exactly the question. Is this situation a problem or could it become one?

I find the situation strange. In my profession, something like that wouldn't be acceptable. You create a plan/contract, both parties sign it, and then there's no back and forth about who agreed to what, when, where, and how. But based on your answers, I conclude that it's different in construction and absolutely normal.