City villa 200 sqm with gallery - optimization suggestions

Hello hello,

I would also like to use the knowledge and ideas from the forum here to optimize my design.
I look forward to open words and criticism of my self-made design :-)

Here are the facts:

Development Plan/Restrictions
Size of the plot: 1,005 sqm (rural Lower Saxony)
Slope: no
Floor area ratio: 0.4
Plot coverage ratio: no specifications
Building window, building line and boundary: 3 m distance to the property boundary
Edge development: garage or carport with workshop/storage room 8 m length
Number of parking spaces: no specifications
Number of floors: 2 full floors
Roof shape: no specifications
Style: urban villa
Orientation: house entrance north side, garden with terrace south side
Maximum heights/limits: max. building height 9 m
Other specifications: max. 50% of the plot area may be sealed; unsealed area must be designed as green space. On the south-west boundary of the plot, a 3 m wide planting strip with a hedge must be provided. Rainwater probably has to infiltrate on the property – therefore installation of a rainwater tank/cistern.

Owners' Requirements
Style, roof shape, building type: urban villa, hipped roof with 25% pitch, solid house (monolithic)
Basement, floors: no basement, 2 full floors
Number of people, age: 2 people (both 28 years old), 1 to 2 children planned in the future
Space requirements: see design; on the ground floor: 1 additional room for guests/office; attic as storage space (not developed)
Office: family use or home office?: family use
Guest sleepers per year: not regular
Open or closed architecture: open
Conservative or modern construction: modern
Open kitchen, kitchen island: both yes
Number of dining seats: 8
Fireplace: yes
Music/Stereo wall: yes
Balcony, roof terrace: no (terrace to be covered later)
Garage, carport: double garage or double carport (depending on budget)
Utility garden, greenhouse: possibly later
Other wishes/special features/daily routine, preferably also reasons why this or that should not be: open living/dining/kitchen area because I like to cook daily and for a long time and don’t want to stand alone in the kitchen. Gallery with large window area because I like the open design very much. Due to my partner’s shift work, we often sleep separately – therefore we want to provide another room on the ground floor as an office/guest room for this. In old age, this could also become a barrier-free bedroom.

House Design
From whom is the planning: from myself
What do you particularly like? Why?: 15 sqm air space (creates a lot of light and spaciousness), large living/dining area with open kitchen (cooking is my hobby and I want to be part of the action), south-west orientation of the dining area with terrace (evening sun), bathrooms one above the other (reduces costs), direct access from the bedroom to the dressing room and bathroom
What do you not like? Why?: Due to load-bearing walls above each other, one children’s room is significantly larger than the other (the large children’s room could be smaller). I would like a small storage room on the upper floor. It would be nice if the entire living area could still be optimized/reduced a bit.
Price estimate according to architect/planner: own price estimate 500,000 including ancillary costs and carport or garage
Personal price limit for the house, incl. equipment: 500,000
Preferred heating technology: air-to-water heat pump with underfloor heating

If you have to do without, which details/extensions
-can you do without: walk-in dressing room and bathroom from the bedroom
-can you not do without: large living/dining area with open kitchen, gallery, guest room/office on the ground floor

Why has the design become what it is now?
I have been working on the design since September 2020 – this is the 2nd design.

What is the most important/basic question about the floor plan summarized in 130 characters?
Optimization/reduction of living area (cost saving)? Are there any major design errors?

Pretty big place - is 500 thousand enough in rural Lower Saxony?

Budget should be tight even for Niedersachsen. The gallery has been discussed often enough here in the forum. Openness transmits noise. This can be disadvantageous with 4 people. Upper floor Access the parents' area through the dressing room. Especially with different sleeping times. Getting up to the dressing room quietly and no matter how often you have to go to the closet, the partner can sleep Shower rather narrow I find the second children's room too small compared to the rest. What bothers me much more, especially in the large one, are the mini windows. No vampires are moving in there. Guest/workroom bathroom is not barrier-free. Cloakroom is missing Building services/utility room/storage room is very tight. At least remove the door to the garage. Dining area with 3.14 m is very tight. Draw a table with occupied chairs. Minimum distance from table edge to wall is 80 cm. That means, like with a bench, when everyone gets up, someone has to go to the toilet. I find the arrangement of the kitchen inconvenient. Too far away from the dining areas inside and outside.

Thank you very much in advance for the first suggestions for improvement :)

As already mentioned, my goal was also to design something smaller, especially regarding the costs.
Budget-wise, I have initially set 2000 €/sqm. That would be 400,000 plus additional costs and buffer. I will prepare a cost calculation this month...
I am hoping for somewhat lower construction prices here in the region. We were able to purchase the plot for 58 €/m2.

The cloakroom should be next to the armchair in the hallway and in the stairwell.
I think the showers are well dimensioned with a width of 1 m.
In the technical/utility room, one side should be for the technology and the other side for washing machine, dryer, storage, etc.

Regarding building services
draw everything in a bit. ours would not fit. with dirty laundry, washing machine, dryer, sink the wall is full. storage space, supplies, cleaning stuff where?
wardrobe for 2 may work, for more no longer

Hip roof with 25% pitch

Are you sure? That corresponds to 11.25° ;)

However, I also think that the budget will not be enough. We are building something larger but with simpler architecture and will not manage with 500 K. The pure base price might fit for you, but then additional costs and extras come on top.

Edit: The extras then naturally include garage and fireplace. Just these two items should amount to at least 50 K.