General procedure / schedule

You somehow don’t realize that your rigid fixation on "Fertighaus" alone stands in the way of your otherwise "normal" wishes for separation and personal contribution.

And with this fixation, I really wonder what you’ve been listening to for 8 hours a day!?!

Detach yourself from Fertighaus, then it will make sense. But others here have already told you this several times and it only supports the thesis of my last post.

As I said, I would like substantiated facts

You haven't spoken to any provider yet, but you want "substantiated facts" from us? Do you see us as your personal assistants or something? You get input here, you can accept it or reject it assuming your incredible market power.

Here is a substantiated fact: the plot opposite is being divided, the two owners are in planning with Hanse and Schwörerhaus. With Schwörerhaus, if the contract is signed in June, the house can likely still be produced in 2022. The building application must then be approved in summer. For the Hanse couple, the estimated delivery date is about 24 months after building permit approval. So much for capacity. Even "smaller" companies have full books.

Do you mean the FHA tells you how full their books are?

Yes, at least indirectly, by giving you a scheduled appointment at the end of 2021. They don’t do this to annoy you, but because they are now processing orders from last year (or even the end of 2018).

I basically just want to save costs and maybe take different routes or shape the offer in advance (e.g. through a preliminary sampling) so that I won’t have an extra €100,000 in the sampling.

That EXACTLY is what is so exotic and therefore so difficult. Taking different routes, only saving costs, preliminary sampling. Let that sink in – you have exotic special requests.
Try that, for example, if you want to buy a car. Dear VW salesman, I’d like to save costs and therefore work as an intern in production. Call the ambulance already, because the salesman is running out of breath from laughing fits...

With Schwörerhaus, if the contract is signed in June, the house is likely still to be produced in 2022. But then the building application must be approved in the summer. For the Hanse couple, the likely delivery date is agreed to be about 24 months after the building permit. So much for capacity. Even "smaller" companies have full order books.

Is it really already that extreme????

thanks, I will keep that in mind
I am here in a forum where many different opinions can be read, so I ask for facts, nothing more.
I understand. But when buying a car, I know in advance what I am looking for. I don’t buy a standard car and then wonder that the 360° camera suddenly costs 5000€ extra. I never said I want to lay the screed myself, but simply want a cost breakdown in the offer that is at least 90% final, with no or few surprising costs, and that simply through savings, certain DIY tasks, and self-contracting. Don’t get carried away with such unnecessary condescension, I don’t do that either. This is not kindergarten here.

Just ask a company with your ideas, and then come back here. At the moment, it makes no sense to continue responding because you do not accept anything that does not fit your ideas.