Single-family house floor plan / Feedback, criticism and suggestions

Indeed, in this plan the garage would be a solid construction, meaning the garage exterior wall is the same as the house exterior wall. However, I would build the exterior wall of the house and later want to add a carport or an FT Garage Rekers if the lottery win described above occurs.

Unfortunately, I relied too much on prices of 1,800 euros to 2,000 euros per m2 of living space in our cost estimate.

Ordered by chronology:

I am flirting with self-employment and considering possibly creating a separate work area here, independent of the storage.

That is good. However, I would rather see the storage space on the ground floor, so you don’t have to carry boxes all the time.

that we currently live in a single-family house with 150 m2, and it feels like everything is full. With things that I couldn’t imagine before we had children. The attic is also full; regarding the attic conversion, I would first like to install a proper staircase to the attic floor.

I think I am right in advising to declutter first. And that BEFORE the next floor plan is drawn up.
Four-person families also do well with 140 sqm. Okay, with a bit of discipline. But what you describe sounds a bit like hoarding. Keeping. Holding on to unnecessary things. A four-person household should manage with normal room sizes and 20 sqm of storage space.

Build smaller. Build more efficiently.
Where or in which places/areas would you build more efficiently?

already said everything in #3!!!

The counter-designs no longer correspond to our ideas, however

That will be because of the budget the general contractor sticks to, but you don’t.

To get to the living room or kitchen, you first have to go to the end of the house and then turn back.
Would you arrange an additional door from the hallway?

Not at all. I consider the basic planning to be wrong. It’s not bad because you don’t know better as laypersons.

I don’t see a wardrobe
The utility room (HAR) as a passage room to the hallway should be used as a wardrobe.

Also not nice!!!
Sorry, but you are planning 225 sqm with oversized rooms, a lot of empty space, and long corridors, but important things like a wardrobe for four people are accommodated in a leftover corner of the utility room.

Thanks for the site plan. South is probably diagonally down???????
I would put a completely different house on the plot – with a different orientation of the rooms, sun in the living areas, relocation of the family room, etc. You have so much land, a lot is possible. But within the budget. The current plan is a dream in terms of size. And hand on heart: do you want to have your storage space you are currently missing in the living room and the empty hallway extension between the living room and kitchen? Or how did the idea of the family room come about?
Financially, that castle in the air is not possible. Delete, crumple, destroy and stay grounded with the next draft.

For the children's rooms, move the doors so that a wardrobe can still be placed behind the door. On the wall against which the door hits, there is usually a wardrobe; if the doors stay where they are, then the wardrobe can only be placed where the open door ends, and when opening the door, you always stand in front of a wardrobe...

Unfortunately, I relied too much on prices of 1,800 euros to 2,000 euros per m2 of living space in our cost estimate

I am not familiar with the prices in the Hannover region, but I would argue that the train has long since left the station. Unfortunately, I can only agree with the others regarding the floor plan. Somehow, it's still not quite right.

I am toying with the idea of becoming self-employed and am considering creating a separate workspace here, independent of the storage area if necessary.

Then you should definitely finalize your financing beforehand, otherwise I see at least one or two waiting loops before you can get started.

However, the counter-proposals no longer correspond to our ideas.

Don't you wonder why that is? Because – as already said here – the design cannot simply be shrunk to the desired small size with Photoshop.

The hallway room HAR to the corridor is to be used as a wardrobe.

That is at least an unusual consideration.