Floor plan single-family house approx. 160m², main entrance in the basement, north slope 1700m²

Who owns the strip between the property and the street?

Is there already a plan from the surveyor?

The excerpt from the cadastral map is indeed very small. But is it certain that it is building land? The steep slope, not to mention the retention basin, confuses me. There is also no neighboring development? For Par 34, you have to orient yourself to the existing development. Is there a larger section or maybe a screenshot from Maps?

Thank you very much for the numerous responses. We are positively surprised. The reply took some time because we first had to internalize some points and because we lost the forum draft in between.
So far, we had not really considered the earthworks. Before taking further steps, we need to take a closer look at the earthworks. Also, many thanks for the tips regarding the floor plans.
The search and selection of the plot is currently limited since we are not yet ready to expand the search radius.

Fortunately, subjective feelings may vary. We like the plot with its possibilities. For this reason, we simply imagined cutting back the slope to the rear and capturing it with plants and stones to create more level garden space. We are very grateful for the professional assessments regarding terrain modeling, as we lack expertise here so far.

The consensus seems to be that the plot is unsuitable. Now the question arises whether we should even consult an architect or if our budget for the plot and our wishes is simply too small?

Are the incidental construction costs including earthworks and retention included in the budget?

Our budget (total approx. 800K) currently looks as follows:

[*]550K house + building technology (photovoltaics, heating, fireplace)
[*]83K plot + incidental purchase costs
[*]8K construction supervision
[*]25K surveying, development, small sewage treatment plant
[*]60K earthworks & exterior facilities (preparing building base, terrain modeling, driveway) --> biggest uncertainty so far
[*]5K rain cistern
[*]20K kitchen
[*]20K terrace (completion in 3 years)
[*]approx. 30K buffer

I would miss direct access to and a view of the garden when planning for 3-4 children.

We cannot follow that.
North of the terrace (downhill) only the driveway and carport are planned. The garden is therefore in the line of sight from the kitchen/dining area.

The first rule for a hillside house is to go to an architect. Those who avoid this will get a standard house from the general contractor, which does not integrate into the plot.
As can be seen here, a small turret.
The problem is that a general contractor does not take care of terrain modeling, where incorrect planning either results in the plot not being properly used and/or very high additional costs for drainage, modeling, and exterior design. However, this has nothing to do with the general contractor but will be an additional task for you.
It starts with the driveway to the garage and ends with drainage (what comes from above). One can easily sink a six-figure sum here. The retention basin is not there for free.
Regarding the house and budget: without the exterior facilities, I see just under 240 sqm. The garage is included in the thermal envelope. That could result in house costs of approx. €680,000 plus incidental construction costs.
A planned 7-room house is not feasible with 140 or 160 sqm.
160 sqm on a flat plot costs about €480,000... here an additional finished basement is added.
I see it the same way as : the wrong plot for you or another normally earning builder.

We are a bit surprised by the 240 sqm. The designer’s draft has just over 160 sqm as indicated in the title. Apart from the layout on the ground floor, we are satisfied. 80 sqm more living space is unnecessary for us. But maybe the designer uses a different living space calculation?
We try to keep the house as practical as possible and not wasteful with living space (which also has to be cleaned). Hence also the idea of the garage (which the general contractor’s designer has planned outside the thermal envelope).
Creating even more living space in the basement as suggested by and is currently not in the budget.
The main problem as we see it, besides the slope, is that we have too large a spatial requirement on the ground floor, which then enlarges and makes more expensive the basement and upper floor.
The following options are currently not feasible for us:

[*]another plot and then no basement (we currently do not want to enlarge the search radius)
[*]no work/bedroom on the ground floor (otherwise the bedrooms with WC on the floor are insufficient)

Who owns the strip between the plot and the road?
Is there already a plan from the surveyor?

This parcel belongs to the public road. See aerial image attached.
So far, there is only a very rough elevation plan from the soil survey from 2021, which is available to us. We want to commission surveyors only once/if a notary appointment takes place.

The excerpt from the cadastral map is very small. But are you sure that it is building land? The tremendous slope and the retention basin irritate me. There is no neighbor development either?
With §34, you have to orient yourself on the existing development.

Is there a larger section or a screenshot from Maps?

It is a plot in a small new development area with 8 plots without a development plan. From gable to hip and flat roofs and 1 to 2½ stories everything is present.
The plot is described by public authorities as a building plot and is also in the inner development area.
The retention basin is necessary for the small village stream due to the additional sealing of the 8 plots.

If I only add up the square meter numbers from your plans - excluding garage area - I come to just over 200 sqm. Since the garage is within the thermal envelope, you get about 230 sqm of usable space. Multiply that by 3000 euros/sqm and you already have 690,000 euros just for the construction of the house on the invoice.

And the visibility of the garden from the first floor wouldn’t be enough for me - I would miss the direct garden connection. We once rented a house where we always had to go through the basement to get to the garden. I would never willingly build that. Except with a big terrace on stilts and stairs to the garden. But that would add several thousand euros extra.

I see the uncertainty in the slope, which we cannot grasp. You do have a cross-section there, but apparently it is very shortened. What if you actually draw it out in full length and calculate how much earth movement or excavation effort is required? How many cubic meters have to be moved to get even a small real flat area in the garden? A mound can certainly form at the property boundary, but you want some ground to walk on and cultivate. The children also want to play on a level surface, not just use a sledding run in winter.
How many embankments must be retained at what height? That can really hurt financially. What is certain: the usable area will shrink considerably. In the end, you can be glad to have a flat lawn area the size of a 500 sqm property.

Raumbedarf im EG, OG: jeweils ca. 70 qm

2 Erwachsene ca. 30 Jahre + 2 Kinder (0 und 2 Jahre), geplant insgesamt 3-4 Kinder

Then I see a problem in that you cannot estimate how much space you actually need. Currently, I see only 2 children's rooms, two workrooms, one guest room and one multipurpose room of average size, which should be enough with two children, but with 4 children there would definitely still be a lack of retreat space. And yes, I am aware that you can use the study as a children's room.

Verwandtschaft 30-50 Nächte

With so many overnight guests, an independent guest room with a small bathroom naturally suggests itself. The guest room in the basement is relatively small and has no bathroom connection.

könnt Ihr nicht verzichten: …, Arbeitszimmer im EG

... which, in my opinion, somewhat contradicts a necessary study on the ground floor. Why does a study have to be on the ground floor?
I would arrange the office by size and location in the basement and then accommodate the guest and bathroom on the ground floor.
The guest room could also be designed as a retreat/TV area when guests are not there.
However, guests might feel more comfortable in the basement if they (being older) want to withdraw from the hustle and bustle.
Then the whole family also benefits from a restroom in the entrance area, which I also think is necessary. The office on the ground floor could be smaller.
Regarding the entrance area: you yourself as well as have noted that there is then a lack of light and sight lines. That is just how it is when you have the entrance in the basement. However, you can also make it attractive and generous. I do not see that here at all. There is no open staircase visible, nor enough space to enter the house and be welcomed by the house. It is simply cramped and small. If you have to give up on sight lines or views of the garden, then you create a nice hallway with enough space for furniture, width and light coming through the door and windows. You plan against deficits. There is almost always a (nice) alternative.

Arbeitszimmer im EG kann als Schlafzimmer bei Gehbeeinträchtigung genutzt werden (evtl. Treppenlift ins UG nötig)

I do not know if you have to plan for disabilities. Since the family planning is not yet completed and you are already about to buy a hillside property, I would put this aspect completely aside and sell the much too large house anyway in old age or infirmity.

Technikraum zu groß?

I do not consider 24 sqm of utility and storage space too much.

Keine Sichtachse von der Flurnische im EG zum Hauseingang vorhanden, um Ankommende mehr in das Wohngeschehen einzubinden

Something like that, as already somewhat described above, can of course also be achieved somehow, for example with a mezzanine/open space. I just do not know if that is so functional when you eventually have dozens of children (your own, visiting children, etc.) coming and going in the house.
However, I could well imagine everything being a bit more open, then the chill area would have to be a bit more separated, in my opinion.

First, I would take the garage out of the thermal envelope, i.e. completely out of the house.
Then I would consider a split level. At least a separate retreat floor or children's floor.
Whether split level, full basement, basement or attic conversion, that all depends on the slope. And as said at the beginning: that is not accessible to us.
Maybe also reconsider somewhat more ground area and plan a basement with a ground floor. And then expand the attic as needed. Possibly bring light into north rooms with a shifted shed roof. Personally, I would avoid such a tower building.

We built on a similarly located hillside plot, but significantly smaller (approx. 530m2)

Costs for earthworks in connection with the shell construction: €50,000
Costs for completion of the outdoor area: €80,000

That was 7 years ago.

Attention: You will probably need a soil analysis, which determines where your excavation can be deposited. The soil analysis is more expensive than the usual "soil report". If any pollutants are found, you will face a cost explosion