Basement or ground slab: which is more sensible for the property situation?

6% slope is just 75 cm in the area of the house, which is easy without a basement. If you rotate the house, it is only 0.5m. I always like to look at how the neighbors solved it and also ask them how the building ground is.

What brings us to Split as another option.

Me to the question of the budget.

What is the reference height for THmax = 6.5 m, FHmax = 10.5 m? An incomplete development plan is useless. What is being planned? Gable roof?

Hi everyone, thank you very much for the numerous contributions, I would like to address the questions:

At first glance, I would estimate that you can still build well without a basement. Terrain modeling will not be avoided in any case. But the basement is then a considerable additional expense.
The question you should actually ask first is in my opinion: What do you need and how high is the budget?
Aside from that, a lifting station is not a disaster. If you are still afraid of it, no one forces you to build one even with a basement.
If I interpret your sketch correctly, you place your house at most on the slope. Perhaps a squarer shape would be somewhat cheaper.

In my view, the following points are relevant for the orientation of the house:

[*] Usability of the garden with reasonable lighting
[*] Visual connection to the castle (or North-East side, which would of course also work with a different orientation)
[*] Garage/carport on the Northwest side (by the sidewalk)
[*] Usability/orientation of the roof for photovoltaics (the property is in BW, so mandatory and also desired)
[*] For this reason and also to avoid additional costs and create storage space, I also plan a gable roof

But I agree with you, a square floor plan would certainly also work regardless and have slight advantages regarding the effort of terrain modeling. As already mentioned, I think you can't avoid a 1 m retaining wall in the northeast (the two adjacent properties have already implemented this)...

More gladly tomorrow. For now, briefly: with "(11ant) basement rule" / "basement question" you can find my contributions here on the topic of your property's opinion about basement yes or no or possibly partial basement. Whether the excavation is good for backfilling depends on its quality. In any case, it is loosened compared to its previously installed state, so it requires compaction. Backfilled, it does not have the same volume as excavated.

That is nonsense. The property and especially the building area are not so huge that this would result in a multitude of test sample points. I would simply select the inner circle of the building area here.

Thanks for the assessment, could you mark on the concept draft points where, in your opinion, test sample points (including garage/carport in the northeast) would be necessary and how many?

Basically, with the slope you have the problem that you are stuck between two stools. For a pure flatland plan it is too much slope, for a hillside house too little. In your considerations, you should also always take the entire outdoor facilities into account. Where will the terrace go, how do you want to get from the house into the garden (stairs?), where would be the light well of the basement office? What makes more sense also depends a bit on your requirements (e.g. how often do you use the office?). Ultimately, two very different floor plans come out here in two variants. Therefore, I only want to address one detailed question.

Excavated soil can of course be used for embankments, but most soils cannot be compacted in a controlled way and you have to expect settling. You can do lawns and flower beds there, but you must build a driveway on gravel.

I have supplemented the concept draft with a possible terrace, light well and driveway. Steps into the garden might still be okay, but the terrace should of course be level. An older architect gave me the following opinion: "who sits lower always loses, they don’t want to sit lower than their neighbors, etc...". The use of the office is definitely given (2-3 days a week).

Which brings us to split levels as another option. It doesn't always have to be half a floor. Sometimes 2 to 3 steps just on the ground floor are enough to produce a noticeable effect. That also often allows for very nice zoning.

Interestingly, I also considered split levels as an option at the beginning of the project. However, none of the architects etc. really addressed this topic (despite my hints). Besides the advantage of better terrain utilization, I also see the advantage of creating a locally more spacious feeling in the living/dining/kitchen area etc.

A 6% slope in the house area is only about 75 cm, which is easy without a basement. If you rotate the house, it’s only 0.5 m.

I always like to see how the neighbors solved it and also ask them how the building ground presents itself.

As mentioned, the neighbors simply filled up to street level, or almost to street level, and set retaining walls etc. From a cost perspective, I consider this solution questionable and find that a plot with a slight slope, etc. can be much more appealing than just a flat filled surface...

Regarding the budget question.

The budget is not yet 100% fixed (mainly depends on interest rate development). I currently assume that about €550k is feasible, or I consider this amount appropriate (but €600k would probably also still be possible).
The property is already purchased and fully paid, i.e. the mentioned amount is available for:

[*] House construction including ancillary costs and equipment
[*] Driveway
[*] Garage/carport including storage room for bicycles (possible item to cut)
[*] Cistern (possible item to cut)
[*] Photovoltaic system
[*] Garden (especially terrace)

What is the reference height for THmax = 6.5 m, FHmax = 10.5 m? An incomplete development plan is useless. What is planned? Gable roof?

As already written, a gable roof is planned, but almost everything is permitted. I have attached the information from the development plan. Two full floors are also permitted.

Finally, I would like to note that the neighbor in the southwest planned a garage on the property boundary, but currently cannot build it (because the filled-up plot is too high and not approved). If I were to fill up, would that be possible then, and there is also the wish that I take over an easement (which would become void again after filling)...

In conclusion, I would like to add that the neighbor to the southwest had planned a garage on the property boundary, but currently cannot build it (due to the raised ground, it is too high and cannot be approved). If I were to raise the ground, would that then be possible, or is there also the desire for me to take over a construction encumbrance (which would become obsolete after raising the ground)...

Had a good laugh again. Thanks for that!
Personally, I really don't like senseless filling. Here, your neighbor has shot himself in the foot with that, and you immediately found someone who will pay for your terrain modeling on the side.

All prefab house providers etc. that I have been in contact with so far have really addressed these circumstances,

That is quick and easy to explain: Prefab house providers usually do not offer basements and have to refer to partners, (also floor slabs, but that is straightforward and unproblematic). Moreover, a basement often, very often, also in combination with prefab construction, causes problems. People are reluctant to discuss that, because problems do not win customers.

What advice can you give me regarding soil surveys (exact later construction not yet fixed)?

Since the plot is not very large, it should be sufficient to roughly know where the house will be located.
You have already started with that. So you should roughly know where what could be.
SO living rooms and terrace, NW utility rooms. I would push the house further to the NE and have the terrace in the SE or also a SW garden. That already gives two points for the drilling of the soil survey.

to create a basement room with daylight facing northeast that could possibly be used as an office.

That additionally means, due to the higher basement costs, taking the basement INSIDE the thermal envelope and finishing the basement as living space. Just for one room…
At about 70cm I see absolutely no reason to think of a basement. I also see no reason to think much about filling or similar. The 10cm in front is balanced with gravel or driveway material.
The front door is the next level, and the remaining garden to the NE with very wide steps in the lawn, thus across the whole property. The house foundation can be balanced with planting or raised beds. It is only at the back. The rest will sort itself out. If necessary, you can always still build the expensive

retaining wall

at the back. But I see no necessity for that. At least not with the current information and status.
Best is to draw out what options you have.
Paper, colored pencils and many templates, then photos with the phone for comparison.

backflow valve

I don’t even know what that is.

Basically I would not have filled in necessarily, but because the plot has been raised on the southeast side and the main light also obviously comes from there, I almost feel forced to make at least partial filling.

??? Your main light comes from above, and the hill is nothing.

Northeast, at some distance, there is a castle that should also be considered in the planning of the house (view connection).

Nice!! Bedroom would be suitable there, right?
We have a cathedral that never really became a cathedral… we look at their church tower from the toilet. We have more than one cramped window in the living room because of that. Maybe that will come up for you again.