Detached house ~ 150 sqm for 5 people

Cool! Thanks I really like the idea of making the cabinets in the niche disappear. But I haven't gained any space with that, have I? And you would have to design the niche so that ,,standard,, cabinets fit flush, or you could only use ,,custom-made,, ones if no standard sizes are possible. But we will definitely take a closer look at that calmly!

Actually, at least in the lower room, only a cabinet would fit to a limited extent in the original plan since it would partially collide with the door. This way, you could even install a sliding door cabinet in this room, where the rail could also run along the unusable wall on the left side. That would make the floor plan of the worst room (nominally the second largest but the hardest to furnish due to the missing dormer) even more usable because the swing area of the cabinet doors would largely be eliminated; you can move closer, for example with an office chair. Furnish the floor plan and experiment with the division and depth of the partition wall. For sliding doors, about 65 cm for the furniture (plus 4 cm plaster and baseboard) is a typical dimension.

Of course, at the latest with a sliding door, a carpenter would be advisable. But there are also online cabinet planners for that, with delivery. How high is the wall, up to the gable or from when does the attic start?

In the other room, you can pick a cabinet and push the floor plan accordingly until it fits. Keep in mind that you will need 2 cm of plaster on each side plus about 1.5 cm clearance for the edge strips. And the wall can sometimes be 1 or 2 cm off. A drywall partition would probably suffice here, with insulation about 10 cm instead of 17.5 as in the plan. That gives you a few more centimeters—and those are exactly what I would really fight for in the children's rooms.

Let's put it this way: apparently, so much practice was done with the staircase here that something botched came out.
Everything could be straightened out by moving the staircase. The one to the attic could get the staircase opening. The storage room on the upper floor would become larger and could also serve as a closet space. You wouldn't have the slanted corner anymore. The logic of going into a dining room to then get to the living room exists rather than the other way around.
Look at the argument from : you will certainly get a lot of visits from the children's friends and have constant foot traffic in the evening, even if you want it to be cozy.

Assuming we move the staircase. Then I would have to shift the staircase "upwards" (south on the plan). Then all the walls + the door to the living room would also move back and the entrance to the office would disappear or rather be in the hallway.

The advantage of this variant, from my point of view, would be:
- Storage room upstairs better usable
- I walk straight into the hallway upstairs

Disadvantages I see:
- Laundry room and hallway downstairs become larger and the living/dining area becomes smaller
- Entrance to the office is no longer located in the living room as desired
- Where would the staircase to the attic be then?

No, at least in the lower room a wardrobe would only partially fit in the original plan since it would partially collide with the door. This way you could even install a sliding door wardrobe in this room, where the rail could also run along the unusable wall on the left. This makes the floor plan of the worst (nominally the second largest but the hardest to furnish due to missing dormer) room even more usable because the swing area of the wardrobe doors is largely eliminated, you can move closer, for example with an office chair. Furnish the floor plan and play with the division and depth of the partition wall. With sliding doors, for example, 65 cm for the furniture (plus 4 cm plaster and molding) is a common measure.

Of course, with a sliding door a carpenter would be advisable at the latest. But there are also online wardrobe planners for this, with delivery. How high would the wall be, up to the gable or from when does the attic start?

In the other room, you can pick a wardrobe and shift the floor plan to fit it. Keep in mind that you will need 2 cm for plaster on each side plus about 1.5 cm of clearance for the baseboards. And the wall can sometimes be 1 or 2 cm off. As a partition wall, a drywall partition would probably suffice here, with insulation about 10 cm instead of 17.5 cm as in the plan. That gives a few more centimeters - and I would really fight for exactly those in the kids' rooms.

Good point, you're right

- Utility room and hallway downstairs become larger and living / dining area becomes smaller
- Entrance to the office is no longer, as desired, located in the living room
- Where would the stairs to the upper floor be then?

I assume the building envelope is not limited to 10m or similar. In this respect, you can pull a bit on one side and push a bit on the other, and it will work again. What is actually supposed to go into the apex? What roof pitch is planned? How high is the knee wall?

Let's assume we move the stairs. Then I would have to push the stairs "up" (south on the plan). Then all the walls + the door to the living room would also shift, and the entrance to the office would disappear, or rather be in the hallway.

I would then change the direction of movement.
Concerning the living room: I wouldn't see it as a disadvantage that a few square meters in the new living area would be lost. The utility room gains real storage space.
Upstairs: The already not particularly suitable cupboard corner disappears; in return, new and larger storage space is generated upstairs, as the stairs can be stacked.

You just have to draw it and let it sink in.
I'll put it this way: it is tangled up upstairs, and downstairs I would personally do everything to get out of the non-private living room situation.

I assume the building envelope is not limited to 10m or similar. In that respect, you can pull a bit on one side and push a bit on the other and it will work again. What exactly is supposed to go into the tip? What roof pitch is planned? How high is the knee wall?

No, the building envelope is generous, but you'd have to explain the pushing and pulling thing to me again like I'm "stupid". How would you push? We wanted a 1m knee wall, 45° roof pitch. The front of the attic (i.e. by the staircase) is supposed to be storage space, and the back half my hobby corner.

I would then change the direction of travel. As for the living room: I would not see it as a disadvantage that a few square meters are lost in the new living area. The utility room gains real storage space. Upstairs: the not exactly suitable corner closet disappears, but new and larger storage space is created upstairs because the stairs can be stacked. You just have to draw it and let it sink in. I'll put it this way: it is tangled upstairs, and downstairs I would personally do everything to get out of the non-private living room situation.

I will recreate it in Sweet Home this evening / at the latest tomorrow to take a look at it.