Floor plan - Single-family house with need for adaptation

Hello everyone,

Development plan/restrictions
Plot size: 816m²
Slope: no
Floor area ratio: no
Floor space index: no
Building window, building line and boundary: 3m distance from the street etc.
Edge development: no
Number of parking spaces: no
Number of floors: 1
Roof shape: gable roof
Architectural style: classic single-family house
Orientation: north is up
Maximum heights/limits: no
Further requirements

Client requirements
Style, roof shape, building type
Basement, floors: ground floor, upper floor, attic, no basement
Number of persons, age: 4 (2x30s, 2x<5)
Room requirements on ground floor and upper floor: roughly corresponds to the floor plan
Office: family use or home office? both
Overnight guests per year: 10
Open or closed architecture: open
Conservative or modern construction: conservative
Open kitchen, kitchen island: yes
Number of dining seats: 6
Fireplace: no
Music/stereo wall: no
Balcony, roof terrace: no
Garage, carport: maybe
Utility garden, greenhouse: no
Further wishes/special features/daily routine, also reasons why certain things should or should not be included

House design
Who created the design:
- Planner from a construction company: yes
- Architect
- Do-it-yourself
What do you particularly like? Why? Overall impression
What do you not like? Why? see below
Price estimate according to architect/planner: 320k
Personal price limit for the house, including equipment: 380k
Preferred heating technology: heat pump (geothermal)

If you have to give up, on which details/extensions
- can you do without:
- can you not do without:

Why is the design the way it is now? For example
Standard design from the planner? yes
Which corresponding wishes were implemented by the architect?
A mixture of many examples from various magazines...
What makes it, in your eyes, particularly good or bad?

What is the most important/fundamental question about the floor plan summarized in 130 characters?

We want to build in summer. The following floor plan is what we have in mind (north is up). The house according to the floor plan or its mirrored version has already been built several times and we were able to visit one of them.
Now we would like three modifications:
1. According to the development plan, we are only allowed 1 full floor. The house according to the floor plan would have a knee wall height of 75cm. 100cm would probably still be possible so that it remains only 1 full floor. However, we would like a higher knee wall and would therefore like to inflate the gross floor area on the ground floor by adding a cold winter garden (9-13m²). The ideal position is probably on the south side in front of the living room terrace door. However, if we block both the terrace door and the window with the winter garden, would we lose a lot of sunlight/heat in the living room or would that not be a significant issue? Otherwise, would it be better to keep the window open? Any other ideas?
2. The raw room height on the ground floor is 2.64m as standard. Since we want underfloor heating, this seems a bit low to us. If we increase the height, the staircase would probably also have to be bigger/higher (more steps). Regardless of the exact increase, what do you think is the best way to create space for the larger staircase in this case?
3. The bathroom on the upper floor is a bit too tight for us (an additional 50cm would be good). If we simply shift the staircase a bit, it would either protrude into the hallway on the ground floor or we would have to make the guest room narrower. We would actually like to avoid both. Is expanding the house the only option or do you have an idea?
4. We will have the building notification and structural engineering done by an acquaintance who lives/works further away. With the documents (drawings, etc.) and further concrete wishes, we would then write to local construction companies/general contractors for an offer. Does that sound feasible and does anyone have experience with this approach?

Thanks, thanks, thanks.

Price estimate according to architect/planner: 320k Personal price limit for the house, including equipment: 380k Favored heating technology: heat pump (geothermal)

I estimate 180sqm. At the often mentioned minimum of 2000 Euros/sqm, this will be a very tight squeeze even with your limit.

I estimate 180 sqm. At the often mentioned minimum of 2000 Euro/sqm, this will be a very tight fit even with your limit.

What about a conservatory, bay window, geothermal energy, higher ceilings? What about garage, driveway, etc.?

If the house, even if mirrored, has already been viewed and basically considered buildable as is, then why more knee wall?

We are having the building notification and structural engineering done by an acquaintance who lives/works further away. With the documents (drawings, etc.) and other specific wishes, we would then write to local construction companies/general contractors regarding an offer. Does that sound feasible, and does anyone have experience with this approach?

At the very least, the process is backwards. Structural engineering is specific and makes no sense before changes by the draftsman of the general contractor (who, by the way, also handles the building application). A conservatory should correspond with an appropriate budget. Be sure to first tell more about the property and development plan here; then much more targeted advice can be given to plan the specific house. Using the search term "Eigenvergabe" should easily find all the input I have already given about the awarding process, construction management, etc.

At the very least, the process is backwards. Structural analysis is specific and therefore makes no sense before changes by the draftsman of the general contractor (who, by the way, also handles the building application).

No no, maybe I was unclear. We receive all kinds of drawings and documents, structural analysis, etc. (standard brick dimensions and what needs to be considered), so that any random builder can get started. I once asked the planning company around the corner and they said that they would simply remove the tasks of floor plan planning and structural analysis and then continue from the next step.

If at all, I would place such a unit next to the kitchen to then grow plants in winter, put potted plants, or store vegetables. However, with 180 sqm, I see the budget as more wavering than stable. Making it even bigger upstairs and creating additional space that you don't really need is the wrong direction for me. If not the costly bay window, then at least forgo the third gable (or dormer) upstairs. That way you have at least 10,000 more in the budget and block capacities upwards, so you get what you want. A DN change is also possible. Moreover, the windows upstairs should be widened. I find the bathroom okay as it is. It will definitely be cozier than a ballroom. I would probably leave out the little corridor between the utility room and the kitchen, basically add the sqm of the corridor to the utility room so that you only have to open one door from the kitchen to the pantry. Regarding the bathroom again: you could adjust the wall of the utility room downstairs to align with the kitchen wall (one line), which will move the stairs about 30 cm downward on the plan. Of course, the office will have to give up a bit as well. But upstairs, it doesn't affect the huge bedroom much to give up some sqm. This way, the bathroom becomes a bit bigger.