General recommendations/opinions/concerns

Hello everyone,
I am new here in the forum and hope to get a few opinions, suggestions, or concerns regarding our current plans.
Briefly about the general status: The building area where the prospective building plot is located is currently being developed. We have "relatively" firmly reserved the building plot in advance with the responsible municipality carrying out the development. The intended start of construction would be around spring 2021.
About the attached plan: I created it myself, but please don’t judge too harshly. I have trained as a technical draftsman, but specialized in heating, so I could only include the construction-related parts that I have somehow picked up on the side. Whether it is feasible technically, statically, etc., still needs to be clarified, and I would also appreciate tips or opinions here.
Here is the corresponding list as far as I can fill it out:

Bebauungsplan/Einschränkungen
Size of the plot: approx. 1000m²
Slope: see section, only estimated!
Site occupancy index
Floor space index
Building window, building line and boundary
Edge development
Number of parking spaces: garage
Number of floors
Roof type: gable
Style direction
Orientation
Maximum heights/limits: valley-side eaves height max. 7.30
Further requirements

Requirements of the builders
see plan ;)

House design
Who created the plan:
- Do-it-Yourself
Personal price limit for the house, incl. equipment: with building plot 450K
Preferred heating technology:
presumably heat pump, stove with water jacket, underfloor heating, solar system
Alternative: as above, but gas boiler with underground tank

If you had to forgo something, on which details/extensions
- can you forgo:
- cannot forgo:

Why was the design made as it is now? For example

What is the most important/fundamental question about the floor plan summarized in 130 characters?
-->General opinions, statements on feasibility from someone with more technical/static knowledge

We are grateful for any suggestions and everything is open for discussion ;)

I am not an expert but here is my spontaneous opinion: I find the master bathroom too large in relation to the children's rooms. I would reduce it, move the dressing room mostly out of the middle, and then rearrange the children's rooms and the bathroom so that the children get more space.

I agree with that. As it looks now, it somehow doesn’t go at all...

I find the house very large. Little storage space (only the utility room), but almost 70sqm for the living-kitchen-dining area :eek: Most builders have around 50sqm for this room, with children's rooms of about 15/16sqm. I am not a fan of oversized children's rooms, but 12sqm is only acceptable in a 120sqm house. For that, the parents' area is about 40sqm... yikes... I roughly estimate 180sqm (numbers are unfortunately not clearly readable on the phone) without the extension. 360,000 plus extension/double garage makes 400,000. With additional construction costs, you are then at 450,000 without a plot of land. Read up a bit in the construction costs section. How much does the plot of land cost?

Construction costs do not match the house size or the equipment. Even with your own contribution, you are very far off. The floor plan can serve as a starting point, but a bit more information about what is important to you would be good.

The property amounts to approximately 55k. The own contribution will be the complete heating, tiling, and drywall work by family/friends. Regarding the parking spaces, we have planned the garage relatively large, possibly with an attic. Furthermore, my parents have a large house where items that are not always needed can be stored.