Floor plan single-family house with 2 full floors with approx. 185m² on 575m²

This is an exceptionally neat draftsman’s plan; two points of criticism or problems immediately catch my eye: namely the 24 cm masonry wall of the garage (unnecessary) and the location of the HAR with built-over house entries (problematic).

We find the footprint of the house relatively large, but it hardly gets smaller without a basement?

I am missing representations of the terrain, without which my basement formula is not applicable.

Furthermore, some rooms were aligned according to Feng Shui.

A little bit of Feng Shui is like a little bit pregnant.

We want to and can do quite a bit ourselves and also work in the building materials trade.

Bringing in own labor urgently calls for architectural planning including site supervision. Because of the warranty for trades performed, craftsmen regularly refuse to process supplied materials. Also, you annoy them if you "begrudge" them the procurement margin. So secondly, expect that self-procured materials can only be used for own labor. And first, do not include any possible savings potential in the calculation. Use this pocket money, for example, for outdoor facilities, but under no circumstances mentally deduct it from the price of a turnkey house.

Yes, we are also not entirely satisfied with the pantry; it will probably have to give way and instead larger cabinets will be installed. I think your suggestions are great, we could implement them as is, many thanks.

Ok, price-wise we probably won't quite make it either, we can save a little on the floor area and some of the technology would be optional or possibly retrofittable.

I find the statement that something was planned according to Feng Shui interesting. What is it supposed to be? I see a deficit according to Bagua in the partnership (pantry) – how does that come about?

The Feng Shui was done according to our zodiac signs before the first plan was even drawn up; it was mainly about which sides are good for us and which rooms should be placed there. The open-plan room was designed by us also because of the cardinal directions/sun. The entrance door faces northeast and actually the bedroom should be there too, but that unfortunately doesn’t work because of the stairs. I hadn’t heard of Bagua before, but I will take a closer look at it.

good tip about the garage; would an 11er be enough here? What exactly do you mean by the location of the utility room with built-over house connections? That the garage would have to be further back? Or do I misunderstand? For the basement formula I can only tell you that the plot is almost completely flat; towards the adjacent building plot to the south, our plot drops maybe 5 cm over the 26 m length.

good tip about the garage, would 11s be enough here?

Depending on the roof structure, possibly in sand-lime brick, yes, but I was rather thinking of 17.5.

What exactly do you mean by the location of the HAR with built-over house connections? That the garage would have to be set further back?

Or placed at a distance next to it or something similar. In any case, in the plan the garage is positioned so that its footprint would cover the house connections.

For the basement formula I can only tell you that the plot is almost completely flat; towards the adjacent building plot in the south, our plot drops maybe 5 cm over the 26 m length.

If that is actually the case, according to my basement formula it would argue against a terrain-related "necessity" for a basement; however, then the tip from to insulate the attic becomes more important (though also with a "steeper" roof and a fixed staircase).

Now not about the costs, now about the floor plan. I’ll save myself from reading the possibly already written comments again…

Could the house also be planned a bit smaller? What do you think?

Yes, you almost everywhere have above-average large rooms, about 20% in the children's rooms, the bathrooms, the bedroom, and the freezer room as well as the utility room.

We find the floor area of the house relatively large, but it will hardly get smaller without a basement?

Yes it will. Others plan with 160 sqm, and most then between 125 and 140. Without a basement.

or whether we should insulate the roof after all and thus convert the attic at some point.

What is the purpose of the conversion? You can’t generate living space there. For storing suitcases and decoration boxes, the cold roof is sufficient.

Possibly instead of the double garage only a slightly larger single garage will be built, which would then shift a bit further down/south and in front of our front door there would then be an additional free parking space. This gives us the possibility to move the house further east and thus enlarge the garden west of the house from now 4.5 m to 6-7 m.

I like the idea. My street has the same orientation and those who can, sit there late in the evening in the NW in summer.
Regarding the floor plan itself: I don’t like it!
The main component, the living area, is much too long rather than wide. Rooms are optimal when the walls in a rectangle have a ratio of 2:3 or 3:4 approximately. But not 4 x 10, i.e. 2:5.
Too narrow for the length, too long for the width.
It’s nice that you placed the children’s rooms in the south. There I would also see the dining area, i.e. the center of life. For watching TV, you don’t need a south side. The study is also rather like pearls before swine if you consider that monitors are hard to see in the south and there the roller shutter probably has to be constantly down.
The built-over freezer room was already mentioned.
Carport further back and entrance door also further down on the plan – this will result in more usable rooms because there is space next to the door for a room and thus the corridor does not have to be so long.
I would depict the living area as an L shape, living room in the SE, kitchen in the west, then the spatial effect is nicer and you don’t look directly at the pots from the sofa. If it was due to FS (fireplace stove), I would prefer the harmony of a room without FS. In the NW, the work room and in the NE the freezer room. The upper floor arises accordingly. In the bathroom, you don’t need 3-4 meters of built-in closets, so pay a bit more attention to the sanitary distribution. The pantry is either hidden behind a wall or you leave it out.
The double bed can remain with the headboard facing north.

How is the neighboring development? Often, no low-setting west sun reaches the house or the garden strip because the neighboring house is in the way. Nevertheless, I would still go for a single garage and leave more space on the west side.

I would also arrange the open plan area in an L-shape and put the study where the kitchen is now. It is too narrow there because of the pantry. The rest would have to be rearranged again. The corridor in front of the utility room is actually not necessary; the utility room could also be accessed from the hallway (door under the stairs and the room under the stairs could also be used for utility purposes).

Move the garage to the back, so that it aligns with the house on the garden side, and then place the main terrace in front of the current study (better the kitchen!). Then you won’t be looking at the legs of chairs and tables of the garden furniture from the dining table, but will have a clear view of the garden.

If you can afford it, I would keep the house as large as it is. Upstairs, I find it quite successful anyway. These are spacious rooms where you have enough storage space, even if you plan large window surfaces. The staircase also needs a large window upstairs; then the hallway will get a reasonable amount of light.

But the decision whether you want to downsize should be made first, before it is worth fiddling with the floor plan.