ᐅ Preliminary Floor Plan for a Single-Family House

Hello friends,
as the thread title suggests, we plan to start building our house in 2016 and will begin planning with the architect in mid to late January.
The plot has already been purchased.

Development plan/restrictions: no development plan
- Plot size: 30m * 32m / 960sqm (31ft * 33ft / 10,333 sqft), access possible from south or west since it is a corner plot, to the east a 10m (33ft) wide buffer strip with meadow behind. To the north, the neighboring plot.
- Slope: none
- Site occupancy index (floor area ratio): 0.3
- Number of floors: 2 full floors, no basement
- Roof shape: "modern" gable roof with 17°-20° pitch (desired)
- Style: modern, white house, anthracite-colored windows with external blinds on the ground floor
- Orientation: ridge east/west
- Other requirements: a cistern of at least 3000L (790 gallons) required due to stormwater regulations
- Number of occupants: currently 2 people (29/27); children planned: 1-2
- Space requirements on ground floor and upper floor: spacious open living-dining area on the ground floor with a "separable" kitchen
- Office: office/fitness/guest room
- Overnight guests per year: currently 4, possibly more in the future
- Open architecture: high ground floor with ceiling height of 2.65-2.75m (8.7-9 ft)
- Open kitchen with island: kitchen island desired
- Number of dining seats: 8 people, large dining table
- Fireplace: as a "room divider" between dining and living areas
- Music/home theater wall: "home theater-capable living room," tensioned motorized screen (3.4m (11 ft) wide) + projector, 7.1 Dolby Surround (planned upgrade to Dolby Atmos with ceiling speakers later)
- Balcony/roof terrace: no balconies, terrace on the south side
- Garage/carport: double garage with storage space

House design
Who is responsible for the planning:
- Architect: from January onwards
- DIY with Sweet Home 3D (SH3D)
What is disliked: long hallways, uncertain how long the staircase needs to be with ceiling height of 2.65/2.75m (8.7/9 ft), currently estimated worst case length of 4.6m (15 ft).
Price estimate according to architect/planner: none yet. My estimate: with own work (bathroom/tiles/flooring/paving/painting) about 310,000€
Personal price limit for the house including fixtures: 350,000€
Preferred heating technology: gas boiler with solar system

If you had to give up something, which details/features could you do without?
- Could do without: upper floor can be smaller; kids’ rooms of 17sqm (183 sqft) would be sufficient. I’m not sure which is cheaper: 1) a bay window on the ground floor to connect to the large living-dining area or 2) as in the current sketch.
The double garage could also be a normal garage with a carport.
- Cannot do without: large living room with a minimum 4.2m (14 ft) wide wall opposite the couch. I wanted to place the heating system between the house and garage on the west side.

I would appreciate your feedback.
Many thanks! Greetings from Bavaria

House planning is not my thing.
I prefer to look at costs, and here I must point out one thing to you: build smaller or significantly increase your budget.

Thanks for the tip, I think you're right. Both the house size and the budget are not set in stone. A friend of mine recently built a 13*10m (140 sq yd) house with a double garage for 310,000€ turnkey in the nearby area. Since his house had a hip roof, I was hoping that with a gable roof and similar features, I could stay within the same range.

So far, this is my rough estimate (really just a rough guess; I won’t know for sure until January):
Shell construction: 90,000
Roof: 20,000
House installations: 6,000
Stove: 9,500
Heating system: 15,000
Ground floor plumbing: 3,000
Upper floor plumbing: 7,000
Electrical work: 15,000
Doors: 7,000
Sliding kitchen door: 3,500
Windows: 21,000
Shutters/blinds: 13,000
Front door: 3,000
Garage door: 3,000
Flooring: 6,500
Painter: 3,500
Paving: 7,000
Kitchen: 13,000
Plastering interior and exterior: 28,000

I see you have over 230 m² (2,475 sq ft) of living space planned — to be built in the expensive southern region.

With a basic finish, 230 m² (2,475 sq ft) multiplied by €1,500 equals approximately €345,000, plus the garage, garden, room-dividing fireplace, and additional construction costs. At this size, the total will likely start with a hefty 4, and with some special features and furniture (I already see home cinema, high ceilings — so there will probably be more costs added), you could easily reach into the 500,000 range.

Are you considering KfW efficiency standards? If so, you’ll also need to think about the building services.

You’re right, the size resulted from my limited knowledge of planning. With the design, I mainly wanted to show the basic room layout; so far, every reasonable person tells me the "thing" is too big.
The home theater is already in place; I just need to "move" it. The only addition will be the ceiling speakers.
Regarding KfW, I have to admit I haven’t looked into it thoroughly yet. Until now, I thought it doesn’t make sense to take out "more money" for a "cheap" loan. The architect we have is also calculating with 1500€/m2 (140$/ft² approx.). Now, he just needs to basically "shrink" the house.

Then I recommend you wait until January and visit the forum again.

By the way, your list is still missing garden/terrace including earthworks, garage, drywall construction, all additional construction costs plus architectural services (for a project this size, architectural fees can quickly reach around €20,000), and a cistern.
Also, for example, the floors at €6,500 are very cheap; that’s less than €40 per square meter (around $3.70 per square foot) including adhesive, baseboards, and silicone/acrylic sealant.