Floor plan design for a new single-family house with double garage (city villa)

I could never do anything with air spaces, but why also in the entrance area? What’s the point of that?

Stair end exactly at the door to the bedroom is suboptimal, speaking from experience.

I consider your seating area to be a proper corner; in my opinion, that is not appropriate in a house. But it fits the house style of corners and doors ...

Where would you provide a 2nd shower?

Consider whether you can make ONE room out of storage, laundry, and heating. At the moment, space is also being lost here.

By seating area, do you mean the sofa in the living room or the kitchen island?

Upstairs there is a large bathroom with a shower and bathtub as well as a "children’s bathroom" with a shower. On the ground floor, only a small guest WC with toilet, possibly a urinal, and sink is planned.

Storage, laundry, and heating rooms were deliberately separated. My partner wants a fully equipped laundry room that can also be used for ironing, etc. I could imagine combining the storage and heating rooms if the laundry room and storage room are swapped. Then the garage and storage/heating room would be housed in the outbuilding.

The utility room with washing machine is certainly better situated in the place of the storage room. Depending on how supplies are distributed between the kitchen and storage room, passing through the laundry room is "the lesser evil." Beverages, cool-stored vegetables, and supplies that go beyond everyday use can certainly be a bit further away.

In addition, another washbasin can be useful in the laundry room, and when working there, one does not feel completely out of the way. In this case, the room also needs certain "desire to stay" qualities.

The utility room with washing machine is certainly better located where the pantry currently is. Depending on how supplies are distributed between the kitchen and pantry, passing through the laundry room is "the lesser evil." Drinks, vegetables that need to be stored cooler, and supplies that go beyond everyday use can be a bit further away.

Additionally, another washbasin can be useful in the laundry room, and when working there you don’t feel completely out of the way. In this case, the room should also have certain “appeal to stay” qualities.

This would be our requested change!
Swap the pantry with the laundry room and, if possible, integrate a small storage room into the kitchen. The washbasin should definitely be integrated.
Drinks and other supplies would then be stored behind the double garage.

Straight staircase and open space removed and you have much more room in the floor plan.

Who irons in the adjoining room when watching TV elsewhere or keeping an eye on the children?
Definitely plan a sink for hand washing, even if only stains are being soaked.

What kind of EL do you want to provide?
Even for you, it must be more than flooring and painting work. Don’t forget materials.
House, double garage, ancillary rooms, and incidental construction costs add up.

Just remove the stairs and the airspace and you have much more room in the floor plan. Who irons in the adjoining room when watching TV somewhere else or keeping an eye on the children? Be sure to include a sink for hand washing, even if only for soaking stains. What kind of additional services do you want to provide? Even for you, it has to be more than just flooring and painting work. Don’t forget the materials. House, double garage, ancillary rooms and incidental building costs add up.

I would probably iron in the living/dining room as well, but at the moment my girlfriend still thinks she wants her own laundry/ironing room. A sink will definitely go in the laundry room. I think we will definitely swap the two rooms (storage/laundry room). Whether a pantry can then be integrated into the kitchen without risking an additional enlargement of the total area remains to be seen. I can’t estimate the additional services 100% yet. My girlfriend’s father has a construction company that will cover flooring/masonry work. Here, material/labor costs can be saved. Additionally, he will take over the construction management. He still has something saved with architect and structural engineer, so official rates will not be paid here either. For the rest, we have to wait and see what "connections" are used.

I quickly scribbled something down.
The storage room was replaced by the laundry room.
In the laundry room, a sink should also be installed under one of the windows.
Door from the kitchen removed, creating additional storage space in the kitchen (for supplies) and in the laundry room.
The distance between garage and house is slightly reduced so that the kitchen window can be enlarged from 1m to 1.50m.
The size of the new storage room can possibly be reduced a bit by removing the door to the outside and installing a door from the garage to the outside.