Land planning for new single-family house 180 sqm, with space for a grand piano

Do you play the piano and can you judge that? ;)

And raging children... sorry, is your living room made of plastic furniture and rubber flooring? Children can and should be raised so that they don’t scribble with the pencils on the wooden table or grand piano...
You can also rage in the upstairs hallway, it’s even more likely there because the children's rooms are located there...

Yes, I do and yes, I can judge that.
And it wasn’t about the kids scribbling on the piano, but that I then cannot play in peace.

Making music is usually done together or for others.

No, mostly you play alone at home just for yourself.

That is exactly why my recommendation is to do it as in 3. – namely to go to a professional with the requirement (whatever it is). They can then not only place the grand piano in the room but also take into account things like room modes.

That is exactly right. A music room at home is a dream for every musician – whether amateur or professional.

I am sure that I have not overlooked any indication that the questioner is a passionate amateur musician, and I certainly do not relegate the grand piano from the salon to the upper floor under the approving acceptance of an insult. Rather, the facts are as follows: 1. the client's dissatisfaction with the design attempts already fails on the ground floor - in my opinion causally related to the fact that he started all design attempts with the ground floor (which is the more difficult source for derivation); 2. for one of the two floors (both of which can be full floors here), accommodating a grand piano is on the list of requirements; 3. completing point 2 on the ground floor requires a) more space there than is desired to be provided within the desired house footprint and also leads b) in the case of a full upper floor (consider: the roof pitch here suggests at least a generous knee wall) to an excess of floor area on the upper floor (the development plan does not exclude "Tuscany"-style upper floors, but that would make the house a foreign body in this environment); 4. the client wants to offer the grand piano, as its heir, a place that does not damage its value and does not necessarily see this in a setting like those known from house concerts in villas in Bogenhausen as seen in Derrick episodes.

I am therefore by no means motivated by a philistine assassination of acoustic delicacy when I take up the questioner's own suggestion and encourage him to also recognize a solution to his planning knot in the grand piano on the equivalent upper floor. Acoustic construction would even be more versatile there - keyword partially open roof underside.

Slope
The entire plot slopes from north to south by about 1.2m over 29m, within the building envelope of the house over 13m it slopes by about 0.6-0.80m
(...)
-you can't do without:
The basement is still debatable. My wife is pro basement. I could do without it.

Regarding the topic "basement" and "slope," the basement rule must be observed. 0.8m is already something.

Balcony, roof terrace
If there is space in the bathroom for a sauna, a balcony would be nice. But it will probably be dropped for cost reasons.

I would advise against a sauna squeezed into the bathroom. In my opinion, a sauna needs its own room. Of course, you CAN just make the bathroom so big that a sauna and a relaxation area and XYZ still fit in – then you end up with a gigantic hall which, from my experience, never really becomes cozy.

Friends of mine have this setup and they have
- Wall 1 completely glass windows because of the view (surprise: they are transparent in both directions!)
- Wall 2 the double washbasin unit (which is only ever used by one person at a time)
- Wall 3 bathtub and shower system (only the shower is used)
- Wall 4 is the sauna
The square footage is absurd and it is, from the feeling, the most unpleasant bathroom I have ever been in. It is always cold, no matter how strongly you heat it – except when the sauna is on, then you roast – unless you open the now glued-shut windows… in the middle of the hall the loungers now stand somewhat demotivated.

So yes, if you go by Klafs, they have sleek high-gloss brochures where their sauna fits everything. Better try something like that.

Regarding the topic "basement" and "slope," the basement rule must be observed. 0.8m is already something.

Wall height 6.1m (from top floor ground level) - base height 0.3m (from top floor ground level) - excavation not permitted - backfilling up to 0.5m

As far as I know about basement rules.
we are dealing here with an optional basement, and the builder's wish for a basement with a smaller footprint than that of the main house* would be easily achievable.

*) on this occasion regarding the idea of garage basementing: no, I do not see that here, and as explained in the section "smallest basements" in the third part of the basement series "Alternative basement types and cost reasons" as well as in the second part "Partial basement: the solution between yes and no?", that would also not be such a great stroke of genius.

Regarding the topic " " and "slope," the basement rule must be observed. 0.8m is already something.

0.8 is 0.8. No more! And sometimes only 0.6 ;) Considering that the original poster needs a bit more space on the ground floor because he would like to have a grand piano, a beautiful plot with an unobstructed view, but unfortunately facing northwest, I assume a waiver of the basement so that there is more room on the ground floor. Then a nice sauna with a view can also be accommodated in the attic. I would invest the money in nice things and not in a basement that, if you want to use it as living space, would either have to be set higher and/or require further earthworks. That is neither good for the plot nor for the wallet. And ultimately, there is no space or _room_ left for the grand piano and much more. How does the floor area ratio look: 180 sqm are quickly reached with a garage. Do outbuildings and paving count with the so-called second floor area ratio at 50% extra?