Is base plaster not part of a house?

Therefore, the man on the construction site is more of the craftsman, and he or she should sell functionally well-thought-out buildings as a decent merchant. But I know that the industry is broken, full of amateurs and adventurers.

Hehe, you said that nicely once again.

we requested an offer for a prefabricated house with a basement and garage

If the basement was purchased together with the prefabricated house builder, the overall construction should of course be complete. In contrast, it is common for the prefabricated house itself that the "top edge of the basement ceiling" is the interface from which the prefabricated house begins—also in terms of price and performance.

Basement builders, on their own, often classify basements as solid constructions and do not include such work. In the combination of prefabricated house and basement, it can then turn out to be an additional service from the perspective of both providers.

Here, I see the responsibility lying with the builder themselves to thoroughly read the construction service description. The intermediary of both contracts probably regularly does not think that far. Or did the prefabricated house builder offer the basement (which I suspect was purchased from a basement specialist or a subsidiary)?

So here, in the construction service descriptions, it was mostly standard base plaster and painting done by own work. The surcharge for colored stone plaster was always around 500 euros.

As already mentioned, one should always have the construction performance description checked. Then it would have been noticed. Now the damage is already done. [emoji6]

I think checking is not necessarily required, reading and comparing yourself is not that complicated,

Jo is like that. The provider has no obligation to provide information. What is not agreed upon in the [Bauleistungsbeschreibung] is at the expense of the builder. If the builder feels overwhelmed by this, there are ways to resolve it. One can choose a different construction method or obtain separate expert advice.

You are both right. And yet I see a duty to advise in the case of disability insurance.
Imagine your wife wants a dryer. You are completely inexperienced. Amazon, lowest price first, vented dryer Beko, 199,-. Cool, you think, why burn 699,- for Bosch when 199,- also works. That’s enough for our towels... You go to an electronics store with the same intention. Again this price difference. You tell the salesperson, we'll take the one for 199,-. He should now make you aware that for the cheap one you need a wall opening to lead the vent hose outside. Oh, you think then... We don’t have that. Then it won’t work at all.... Karsten