Major mistakes in the floor plan? Kitchen too small?

I don't find the bay/rear gable quite harmonious, as it sticks out so far. I also don't quite like the combination of the Frisian gable and the captain's gable; I prefer when the same form is chosen at the front and back, but of course, you don't really notice that all at once. Otherwise, your floor plan reminds me of ours. I haven't posted the final one here, but I can gladly send it to you via message. Maybe that helps as a starting point. We also have a wider but flatter gable (4 m*1 m) in the living room and a fireplace (masonry heater) as a small room divider to the dining area to make the living area cozier.

Thanks for your answer, now I have of course become curious. Would you like to tell me specifically WHERE you see this potential? - And I would be especially happy if you could also explain to me WHY [emoji4]

Best regards, Heiko

Gladly.
Friesenhäuser (here my phone actually turns it into a brothel [emoji6]) score with coziness, which is supported by relatively small windows. Nevertheless, if you make the house one or two sizes bigger (you have a floor area of 126sqm plus bay window), on the one hand you have to adjust the window areas, and on the other hand you have to use the gained space.
So far, I only see oversized rooms, but no decent storage room. No, I don’t mean the mostly unnecessary pantry, although I see potential here to add 4-5sqm to the technical room, so that you don’t have everything (recyclables, cleaning supplies, washing machine and dirty laundry, sports and hobby stuff, and the few canned goods as well as beverage crates) in this one room. Decorative stuff and things no one needs anymore will probably end up in the attic.
However, you have to weigh what you need within reach daily.

Yes, the mentioned freezer should, as you say, be on the same level as the kitchen, but you don't go there several times a day, nor to the second fridge. However, with visitors or after sports (possibly in the guest room?), there is such a thing as privacy, which, if you want to build generously, you can also plan for.
In this respect, I still don’t see much brainpower being applied here, instead a lot of unusable empty space. The hallway could show much in its size, but a staircase is planned in the dirty area of the entrance door, where every family member must pass through, also in socks. Using the stairs is a good way to accommodate the wardrobe in a tight space, but what about the jackets and shoes that are quickly taken off only to be put on again immediately?
Representativeness is not just about size...
Same in the living room: lots of empty space in front, which doesn’t really make the seating area (sofa area) cozy. At 6 meters length, you already have to consider how and where a TV can be well positioned.
The bay window: too narrow to be really useful. *Regarding your comment on the size: no, it doesn’t get bigger if you shorten it.* [emoji6]
And if the dining area is actually to go in there, you cannot walk around the table nor open a terrace door.
Kitchen: completely sufficient, only in my opinion the dimensions are not well chosen: the workspace in the triangle is ergonomic when you have about one meter between the rows. The pathway there, which is also drawn here with the tall cabinets, should then in turn be 1.20m. You want to walk through there as well as open doors.
In the upper floor (not only in the upper floor) the windows are much too small for the room sizes. If you deduct the mullions, there isn’t much light left coming through. In addition, because they are narrow without a sill, they do not illuminate the room’s width but more the ceiling and the floor (make a template yourself and take a shoebox you want to illuminate).
The corners in the workroom due to the third gable will not make this room more advantageous either.
Furthermore, you should think about the gable whether not every family member should have a bit of the special character of the house [emoji6]
By the way: the window at the top of the stairs is not centered.

The rooms are designed generously. But rooms are also saturated with usefulness from a certain size – you should think about taking 10% off each and putting that into more practical rooms or built-in cupboards.

Basically, what I’m missing for concrete suggestions are measurements, orientation and location plans as well as exterior views.

P.S. Regarding the sunlight incidence: sunlight decreases radically behind the window. If you give a room more depth, you have to make sure that enough light still reaches there, usually toward the center of the house.

Gladly. Frisian houses (my phone here actually makes a bordello out of that [emoji6]) score points with coziness, which is supported by relatively small windows. However, if you make the house one or two sizes bigger (you have a floor area of 126sqm plus a bay window), you have to adjust the window areas on one hand, and on the other hand also use the gained space. At the moment, I only see oversized rooms, but no proper storage room. No, I don’t mean the usually superfluous pantry, although I do see potential here to add 4-5sqm to the technical room, so that you don’t have everything (recycling items, cleaning supplies, washing machine and dirty laundry, sports and hobby things, and the few canned goods as well as beverage crates) all in that one room. Decorative stuff and things that nobody needs anymore will probably end up in the attic. However, you have to weigh what you need to have accessible daily. Yes, the mentioned freezer should, as you say, be on the same level as the kitchen, but you don’t go to it multiple times a day, nor to the second fridge. However, with visitors or also after sports (possibly in the guest room?), there is something like privacy, which you can also plan for if you want to build generously. In this respect, I don’t really see much brainpower applied here yet, but instead a lot of unusable empty space. The corridor could show a lot in its size, but a staircase is planned in the dirt area near the entrance door, where every family member has to pass through and by, even in socks. Using the stairs is a good way to arrange the wardrobe in a small space, but what about the jackets and shoes that are quickly taken off to be put on again right away? Representativeness is not only expressed in size... Same in the living room: lots of empty space at the front, which does not really make the seating area (sofa area) cozy. With 6 meters in length, you have to look where and how a TV can be placed well. The bay window: too narrow to be really useful. *Regarding your remark about the size: no, it does not get bigger if you shorten it. [emoji6] And if the dining area is actually supposed to go in there, you cannot walk around the table or open a terrace door. Kitchen: sufficient, but in my opinion the dimensions are not well chosen: the workspace in the triangle layout is ergonomic if you have about one meter between the lines. The path to it, which here is also indicated with the tall cupboards, should then again be 1.20 m. You want to pass through there as well as open doors. On the upper floor (not only on the upper floor) the windows are far too small for the room sizes. If I deduct the mullions, not much light remains. Furthermore, since they are narrow without a sill, they do not brighten the room widthwise, but rather the ceiling and floor (try making a template and take a shoebox that you want to illuminate). The corners in the workroom caused by the third gable will not make this room more advantageous either. Furthermore, you should then consider the gable whether every family member should have a bit of the special character of the house [emoji6]. By the way: the window at the top of the stairs is not centered. The rooms are generously sized. But rooms are saturated in usefulness from a certain size – you should think about taking away 10% from each and using that for more practical rooms or built-in cupboards. Basically, I am missing concrete suggestions for dimensions, orientation and location plan as well as exterior views. P.S. Regarding the sunlight: sunlight decreases drastically after the window. If you give a room more depth, you have to make sure that enough light still reaches where it mostly goes toward the center of the house.

Many thanks indeed That was a lot of information and suggestions now... I first have to let it sink in You must not judge the windows yet... that is not quite right. In a week, I can present a concrete first drawing from the architects, then we can discuss it. I will get back to you when I have “digested” your suggestions. Best regards, Heiko P.S. my phone changes Friesenhaus to vacation home.

Edit: checked again now: there are not even floor-to-ceiling windows planned on the upper floor. Therefore, I would take all windows as 3. A 20sqm large room should have at least 2sqm of net window area.

For 3 people, you have quite a lot of rooms. Or is a specific hobby room planned next to the office? Well, otherwise you have enough storage space upstairs. Have you ever considered positioning the guest room upstairs and possibly planning a small shower bathroom there? Then only a guest WC downstairs. Why? Personally, I feel more comfortable as a guest if I sleep in the sleeping area with the rest of the family and don’t have to be the only one awake downstairs next to the front door. The advantage is that you gain a storage room downstairs. Upstairs you have a room left anyway. Then I find the living room inconsistent. The space around the dining table is really tight. Is there a door to the garden planned in the bay window? You would hardly use it with the table in front of it at that spot. Then the seating area in the living room somehow seems lost. Wouldn’t it be an idea to swap the kitchen and living room? So that you really get a niche for lounging on the sofa, can pull the table more out of the bay window, and the kitchen has enough space for a cooking island. The walls with the living room door can be slightly modified then. However, you won’t have a lockable kitchen anymore.

I believe Heiko_baut and Egon12 are talking past each other: here "1.5-story building" seems to mean that there is supposed to be a half-story under the roof slope, and the TE associates a "two-story building" with an apartment villa. Legally, however, there may well be a full story on top, and in my assessment, that will also be the case with the knee wall. Given the combination of steep roof, knee wall, and four gables, I would be surprised if it were otherwise.

I share the concerns of kbt09; in my mind's eye, the bathroom door bashes against the slope.

I am thinking of the bay window as rather shorter than wider. Although I admit that views on pleasing proportions can shift when aiming for steep roofs. In that case, the recurrence may well be somewhat more substantial.