Is a house building offer for a single-family house on a slope realistic?

But he already has his personal one that is valid for his price. Good descriptions of construction services are approved in a watertight manner by several hands, meaning lawyers. Nothing is changed there. But well. As long as the OP does not take the step and asks about his personal services, no conclusion can be reached here.

Oh, sorry, my statement did not quite match yours. But we did have the case where the description of construction services, which became part of our contract, was individualized, for example the concrete ceiling on the upper floor was explicitly specified there. Whether this is common, I do not know.

But okay. As long as the OP doesn't take the step and request his personal achievements, we won't get any results here.

Let's wait and see first. There was an initial rough construction service description which, as we have all already noticed, was not designed for the basement variant at all, balcony is missing, railing etc. There are still some question marks!

Currently, a preliminary draft is being created. I will address all of this, because the construction service descriptions of the other providers were all significantly more detailed. I have the feeling that our general contractor only makes the effort to work everything out in detail when he also knows that we will build with him. The general contractor is not a huge company but has been established here in the region for 30 years.

Unfortunately, I still do not have a drawing, but in the meantime I have a question:

What additional costs should one expect when equipping a normal single-family house with 100 sqm of floor area with a raised basement?

Are there any experience values from anyone?

Are there any experiences from someone there?

I don't think you will find a "suitable" concretely transferable single example. However, your question can basically be answered easily:

What additional costs must be expected if a completely normal single-family house with 100 sqm ground area is equipped with a raised basement?

A ground floor with a 100 sqm slab will already fully absorb the need for a basement underneath, meaning it would then be footprint-neutral. Above ground, its footprint would be fully "on top," so you would first have to have that available in the plot area and in the floor area ratio, which does not sufficiently apply to many currently available building plots.

The basement room itself costs basically the same per cubic meter with the same equipment. Fully above ground, you do not have to account for penetrating groundwater, and usually, a lifting station for wastewater will not be necessary here.

Your comparison is therefore a sum of partly identical items and those that only weigh in in one of the variants. You should thus be able to make the principle assessment apart from "model" numerical examples.

As I said, we have a sloping plot and with such plots, due to the otherwise incurred filling costs, a raised basement is often recommended. Part of the building is constructed into the slope and the remaining part extends from the terrace into the garden area.

I keep reading on the internet about costs of around €2000 per square meter to be budgeted for new residential construction and about €700 per square meter for a good basement finish. If this is incorrect, then I understand your statement. I just thought that otherwise a kind of mixed calculation would apply between a raised basement and good ground floor equipment. Various rooms in the basement don't need a top-notch finish but only serve as utility rooms or storage rooms.

I don't think I need a lifting station, as our wastewater connection is located at the very bottom of the property (lowest point). Even with a raised basement, I would still have about 2 meters of height difference.

Well, a lot has happened and we have also had many conversations. ;-)

With our property on a slope, we had to make the compromise that a living basement is built into the slope and then another floor is added on top with a hipped roof.
The alternative would be a 1.5-story single-family house. But then we would have to add 2-3 meters of fill because of the slope and then terrace the rest of the property. With the variant now chosen, we will get a little more living and usable space (about 85 sqm per floor).

I read nothing here about a high basement, but rather a living basement, i.e., a lower ground floor.

Various rooms in the basement do not need top equipment but only serve as utility rooms or storage/pantry rooms.

And this lower ground floor will become a living floor.
In a "normal" house, you also pay normal living square meters for the utility room and storage room.
It will be no different here.
This will be a normal floor that is partially embedded in the ground, and this then has to be finished as a basement from the outside.