Floor plan house with granny flat - improvement suggestions?

This is not a question to be answered by the wall thickness parameter. The sound insulation argument here is a real knee-slapper in exactly my preferred humor league (note: we are talking about a wall that is bordered on both sides by stairs, with the one of the secondary apartment probably even anchored into it). Apparently, the planner needs considerable tutoring here in both fire and sound protection, but I am a construction pilot (consultant for builders) and not a planner trainer. To the best of my recollection, we discussed the issue of sound transmission most extensively here:

Aha, okay. What would be best in our case? That the floor slabs and the roof structure are separated, so that each apartment has its own floor slab and separate roof structure? How should the wall buildup of the partition wall be? Unfortunately, this thread suddenly ends here:

With a concrete wall, no stones are carried at all; it is shuttered and poured.

In our case, a 30 cm calcium silicate block was planned for the exterior wall (WTW). The block weighs quite a bit. Another option would be 2 x 15 cm for the WTW.

A floor slab does not have to be separated by any means (very unusual), as multi-family houses are also built on a slab and this also provides excellent sound insulation in new buildings when built with the right bricks. Here I recommend lime sand brick; even on the ground floor of a new residential complex, you cannot hear the elevator of the multi-family house or the opening of the front door. Let alone the neighbors or the underground garage below. Although the room is directly adjacent to the entrance door, it is super quiet and the tenants never hear the garage door under the apartment either. That is why you also naturally do not separate the roof truss. I have never heard of separating anything here. But of course, there are those horror stories that unsettle you at the beginning. Because nothing is worse than hearing noises behind the wall in a house with several apartments. So my tip: if you want to be on the safe side, then use lime sand brick. From my own experience, I know that it insulates very well and is also very commonly used especially in new residential construction. Then nothing can happen to you. Whether you are a fan of a double-shell masonry or prefer to build monolithically, I of course do not know.

I don’t mean months... but whatever. I’ll remind you when you get upset about fantasy stone sizes again ;)

So, on the topic, when I’m no longer in the mood and don’t know what to do next, I start decorating my drafts :-D
But that’s a good thing. Because that way I notice what I forgot. In this case, it was the guest toilet for the 5 people.
I’ll show the floor plans and two views.
Of course, the parking situation is not pleasing. One could do without all the inner courtyard stuff, place the HT crosswise and move the house a bit by making it narrower, just as Katja did. But you already have the suggestions, so I’m just adding this idea here.

Thank you very much for your effort; it is an excellent plan - I’m surprised by the creativity. One would want to move into such a house immediately.

Unfortunately, I fear there could be problems with the construction company if we make major changes to the plan. I spoke to the construction company today and informed them that we want to change the plan a bit. They were, of course, anything but enthusiastic about this idea and told me that with major changes the construction project would be further delayed and that we might also lose the price guarantee. Small changes to the floor plan, however, should be no problem.
Since we have a meeting with the construction company next week, I wanted to hear your advice again on how the current floor plan can be modified most sensibly?

The biggest flaw in the current floor plan is that the open space in the granny flat is too small.
There are three possibilities to enlarge this open space:

1. Remove the stairs and the brother enters his room from our apartment.
2. Enlarge the entire house, instead of the current 12.72 m to about 13.22 m or even bigger (which, of course, would make the construction project even more expensive).
3. Option without the brother; the kitchen is moved to the current parents’ bedroom and the parents sleep upstairs?
The option without the brother is becoming relevant again, because because of one person seven others have to make major compromises, which I am slowly no longer willing to accept.

That's why my tip: If you want to be on the safe side, then use sand-lime brick. From my own experience, I know that it insulates very well and is also very often used especially in new residential construction. Then nothing can happen to you. Whether you are a fan of double-shell masonry or prefer to build monolithic, I of course do not know.

That sounds good, we will also use sand-lime brick for our construction project for the interior walls. Now the question is whether 1 x 30cm brick is good enough or if a wall structure with 2 x 15cm is better for sound insulation?

The option without a brother is relevant again because seven others have to make major compromises because of one person, and I'm slowly no longer willing to accept that.

We have... I tried to hint at this to you at the beginning ;) Take a look at #37... although I deleted it again, I roughly stuck to the original measurements. You only have a reclining sofa in the open-plan kitchen (kitchen furniture is just a placeholder)...

I will show the floor plans and two views.

I think this can be accepted as is, and it also works without changing the plot of land.

Now the question is whether 1 x 30cm stone is good enough or if a wall construction with 2 x 15cm is better for sound insulation?

Whether it is nobler in the mind to fear sound excessively ... (?)