Single-family house with a granny flat on a 450 sqm hillside plot

Are there already any comments on the basic idea:

Yes, at the moment I see 4 bedrooms + children's bathroom + utility room in the basement. In the upper floor: living area, bedroom, bathroom + guest WC. I would invest the money for the staircase to access the attic, even if no expansion takes place. Initially only as storage. I would forego the walk-in closet in favor of the living area. To be continued. Good night.... :)

@11ant: Isn’t the draft already above the floor area ratio of 0.4 with 450 sqm and 3 floors? Does something not count here? I’m just not getting it. Can you enlighten me briefly?

I believe the basements are not counted, as long as they are not full floors (?). is missing :-(

At least I will sit down and work on a floor plan, which I will then present here for discussion.

I recommended, mind you, not to start again in the middle of the process: so not in service phase 3. You wrote that you developed a concept with the architect. Based on that, I would recalibrate: how do the prices of the offers actually compare to the “target price”? Maybe my advice from two weeks ago in another thread for a family with a similar offspring constellation will also help you:

Yes, currently I see 4 bedrooms in the basement + children's bathroom + utility room. On the upper floor, open living area, bedroom, bathroom + guest WC. I would invest the money in the staircase to access the attic, even if no conversion takes place. Initially only for storage. I would forego the dressing room in favor of the open living area. To be continued. Good night.... :)

Good morning, thank you already for the suggestions. Possibly I can only accommodate three bedrooms in the basement, provided I do not want the floor area to become much larger. The twins could share a room at first and later move into their own rooms under the roof. Would you plan the entrance to the house on the lower floor or via an external staircase to the upper floor?

Maybe my advice from two weeks ago in another thread for a family with a similar offspring constellation will also help you:

I understand your hint to mean that we could plan two separate residential units on the two levels you suggested (building with a basement, waiving the 1st upper floor) (or at least plan the preliminary installation for a second, autonomous unit) in order to later be able to rent one unit out when less space is needed (children moving out).
However, I might also be missing something. The night with the twins was tough.

I might add that I advised against starting again in the middle of the process: so not in service phase 3. You wrote that you developed a concept with the architect. Based on that, I would make adjustments: how do the prices of the offers compare to the "target price"?

The target for the house providers was always 500,000 euros for building the house as a KfW 40 EE or NH house, the construction of the basement, and the turnkey furnishing of all three levels. The remaining budget of 50,000 euros was planned along with the funding for the groundwork, exterior facilities, and kitchen.
All providers stated in preliminary talks that this might just work. However, exact calculations would have to be done first.
In advance, we still saw some savings potential in outsourcing individual trades as well as by waiving the calculated sliding doors on the ground floor in the offers.
Our currently available offers range between 540,000 euros and 620,000 euros for the construction of the house taking into account our specifications. Exterior facilities and groundwork would come on top of this.

In our case, the architect did not invoice according to HOAI, but the construction company suggested agreeing on a chargeable planning contract. For this, the self-employed but regularly cooperating architect with the construction company held an onsite appointment with us on the plot and revised our plans in two further appointments. The costs were manageable and amounted to less than 1/6 of the amount for service phase 5, assuming a volume of 500,000 euros.

We are currently having our offers independently compared in terms of price-performance, as we lack the expertise to compare various wall constructions and to ascertain why which additional costs are justified where.
The resulting ranking would then also be used when creating an offer for another house design.

It is questionable whether the architect would plan further modifications or a completely new house design under the given conditions. My idea was to already do some preliminary planning so that her effort would hopefully remain limited again. I will definitely follow up to see if she is willing to "make adjustments."

Would you plan the access to the house on the lower floor or via an external staircase to the upper floor?

I am currently struggling with the floor area ratio and the single-story aspect. This is really just a layman's opinion, but if I understand correctly, in your case the upper floor, where a quarter is below 2.30m, is not considered a full floor. So with a knee wall height of 1.80m, a roof pitch of 20°, and a house depth of 10m, the upper floor should not be a full story. I would increase the footprint and accept the sloping ceilings upstairs instead. It would look roughly like this:

[ATTACH alt="efh-mit-elw-auf-450qm-Hanggrundstück-557778-2.jpg" type="full"]69678[/ATTACH]
[ATTACH alt="efh-mit-elw-auf-450qm-Hanggrundstück-557778-1.jpg" type="full"]69677[/ATTACH]

But I really do not know if it works that way with the attic. I need to calculate and research again.
The granny flat and everything else is completely out.
Oops, windows are still missing downstairs in the attic.

Wow, super good!!! How did you manage that in such a short time? I would have only had the exterior walls standing by then. Thank you very much.
That already looks very harmonious.
I tend to stretch the house a bit along the street side and make it a bit narrower. That way, even more of the already quite small garden would remain.
Regarding the floor area ratio, we shouldn't have any problems, as we are allowed to build two full floors according to the development plan. Or does that not matter here? My idea would then be to plan the roof much steeper in order to have expansion potential in the attic. However, this would require modifying the staircase situation again. I'll give it a try now too.