Floor plan for a single-family house with a basement on a hillside

if the entrance is in the north, which is on the ground floor, but the living area is in the basement with access to the garden.

But that is rather not possible. The property slopes upwards... I would rather plan the access in the basement... unfortunately, that is not labeled at all, just like the ground floor is not fully labeled.

But that rather doesn't work. The plot slopes upwards.. I would rather plan the access in the basement.. unfortunately, that is not labeled at all, just as the ground floor is not fully labeled.

True, now that you mention it. I briefly had a different slope in mind.
But all of this is planned completely crosswise to the standard of the plot. You have to go up a staircase outside to get into the house.. that's stupid. Sorry, but I can't follow the heights in combination with the planning. Might be me, or the outdated planning.

A staircase or a somewhat steeper paved path to the front door is supposed to be built on the left side from the street.

That is a height difference of 3 meters (or 1 floor) which you first run past the house on stairs. Of course, you have to plan stairs on the slope and you will definitely have some outdoors as well. Ideally, however, you plan the house entrance so that you don’t have to slide up or down the stairs in winter and simply bring it inside the house. After all, you already have an access via the garage.

Where you want to build the second carport "later", there is then a big pile of earth, which probably borders directly on the terrace with various retaining structures. So if you start to remove this heap later on, you will tear the terrace away because you excavate its retaining wall. So either you build it right away or you better leave it. Or one of us two does not understand the height specifications and designs.

Slope + full basement + estimated 160m2 doesn’t fit with 500,000€.

Apart from that, I agree and think that your budget is too low for this house. The 160sqm alone cost the 500K. The basement would be additional. Then the outdoor facilities and all the rest of the stuff. Depending on the region, you probably end up somewhere between 750K and 800K, I estimate. Does the budget allow that?

Floor area ratio: 0.3 # Floor space index: 0.3
Number of parking spaces: 0/1 # Number of floors: 1.5 # Roof type: Gable roof [...]
further specifications: Roof 28-45°. 75cm knee wall (defined somewhat differently)

What does "defined somewhat differently" mean there – please quote the definition.
And how is the number of floors actually defined: I suspect as U+I+D?

The contractor’s design is useless (except for picking on it and finding as many flaws as possible to clear the way for a new concept). For heaven’s sake, don’t try erasing parts in it and possibly leave everything that is, well, approvable or not "bad" as it is!

This must urgently be completely rethought from scratch. Under no circumstances should the "concept" of this design be followed (must-use basement with garage, then a bungalow on top from the upper floor height). The property clearly says here "no basement, inevitably a lower ground floor," so the latter must also be used as living space, otherwise the house will inevitably be too big. I would even consider placing the entrance on the eaves side directly at the stair landing, i.e. front door/windbreak directly on the eaves side, continuing into the stair landing, and from there it leads into the lower ground floor (street level) and into the upper floor (garden level), I don’t see a main floor here at all, and probably an attic only for storage so that all exposed areas in the lower ground floor can be used as living space. Possibly shared technical rooms, only the house connections downstairs, maybe next to the garage, the rest in the roof. A second uncovered parking space in the area between the street and the entrance. This is definitely a house for an architect; you won’t get anywhere here with just a draftsman.

Which "others", if this is the first from the general contractor? - show me as well!

So far, we have a few initial drafts from other providers. One draft, which we actually liked quite a bit, is attached. However, in the attic floor, everything is a bit tight due to the second bathroom. We would probably still adjust that there.

Don’t you want step-free access to the garden?

Of course we do. We thought that should be possible here. Path past the house, past the front door into the garden. In all other previous drafts, the front door was in the basement on the eaves side. Then you would always have to take the stairs from the basement to the ground floor to get into the garden.
The terrace above the garage is only additional. The main terrace faces south, so behind the house.

Don’t you have any boundary development?

What does that mean? I thought you always had to leave 3m distance to the neighboring property if you don’t have an exemption permit.

I would rather plan access in the basement .. unfortunately, that is not labeled at all

Yes, that was always implemented this way in the other plans as well. We are still not sure what makes more sense for us.

Ideally, you plan the house entrance so that you don’t have to slip up or down the stairs in winter and simply bring it inside. After all, you already have access via the garage.

Yes, that’s a good point. Currently, we assume that we will mostly enter through the garage. But we need to rethink that.

So either you build it in right away or you better leave it out. Or one of us does not understand the height details and drafts.

I agree. We hadn’t considered that so far. Thanks.

Regarding the price: So far, this has only been communicated verbally. But we know of the general contractor having built a similar house at this price.

What does "defined a bit differently" mean - quote the definition.
And how is the single-storyness actually defined: I assume as U+I+D?

Knee wall definition is attached. The zoning plan states WA + I + o

What does that mean? I thought you always had to keep a 3m distance from the neighboring property if you don't have an exemption permit.

That does not apply to garages, carports, parking spaces. They are allowed on the boundary. In NRW 9 meters.

We currently assume that we will mostly enter through the garage.

But not the children, when they come from school. They won’t open a garage door. That only applies to the person who comes home by car, everyone else needs a visible entrance door if possible.

In the development plan it says WA + I + o

WA stands for general residential area, in this context the l stands for a specific WA because the development plan has several different WAs. The regulations for the WA are then set textually or by legend in the drawing. The small o means open construction, so no terraced houses or linked construction.
For example like this

Maybe we are talking past each other. Or I’m confused again. At least that is how it is according to my knowledge. And yes, a full floor is also indicated with an l, but usually offset to the WA. In my example there are 3 full floors in closed development (opposite to o for open).
You could also show a screenshot. The development plan is quite old after all.

But we know of a similar house from the general contractor that was built for this price.

With a basement?