Single-family house with 160 m² - development plan, living area calculation

Why the Auro is supposed to be a two-story building according to the provider’s information with only 75 cm knee wall height, except in Saarland, I have not yet understood.

It is not understandable either. At least not with the information on the provider’s website. The floor plans show a house with a 50 cm knee wall when assuming a 40° roof pitch. With this roof pitch, the Auro only becomes a two-story building in NRW at approx. 1 m knee wall height.

The floor area ratio only refers to full stories.

No. In development plans before 1990, the living rooms and stairs and corridors on other floors regularly count towards it; in later development plans, this can be explicitly regulated, as in the current thread by ( ).

The floor area ratio means that we are theoretically allowed 200 m² of living space.

No. Floor area, not living space.

Do I understand correctly that due to the restriction "number of full stories = 1" the living area on the upper floor may be at most 75 % of the ground floor?

No. Footprint, not living space.

How exactly are the 75 % of the upper floor calculated with regard to the slopes?

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For the Auro on the website (knee wall estimated at 50 cm), the following calculation results (measurements estimated, as not dimensioned):
Ground floor footprint: 7.80 m * 12.00 m + 2 * 4.00 m * 0.80 m = 100 m²
Upper floor footprint > 2.30 m: 100 m² - 4 * 4.00 m * 2.00 m = 68 m² < 75 m² = 3/4 * 100 m² => no full story

First of all, many thanks for the quick and helpful feedback.

I will add the questionnaire right below here or edit the top post.

GD probably means here collectively the category of all pitched roofs.

Correct, according to the development plan, pitched roofs are permitted (gable, hip, and half-hip roofs with a roof pitch (RP) of 15°-45° are allowed). Other roof shapes and pitches are permitted for single-story extensions, garages, or carports.

So if it absolutely had to be the Auro, there would probably be ways and means. In any case, I do not see it as far from a house body possible here, so it may serve the OP as an aid to imagine what might be possible on their property.

It is not absolutely required to be the Auro; it is merely a floor plan on which one could possibly build. But more on that in the next post.

Development Plan/Restrictions
Property size: approx. 25 x 25 = 500 m²
Slope: -
Site occupancy index: 0.4
Floor space index: 0.4
Building window, building line and boundary: 14 x 20 meters, 3 meters to the front and 3 meters to the sides
Edge development: 3 meters to the side space, except garages/carports
Number of parking spaces: 2 cars – usually only one car is used and the other is parked in the garage. Accordingly, the other car could park in front of the garage
Number of floors: 1 full floor (with 1.5 floors)
Roof shape: gable roof, hip roof or half-hip roof with 15 – 45° pitch
Style: modern
Orientation: north (street north, garden south)
Maximum heights/limits: eaves height: 4.50 meters; ridge height: 7.00 meters
Further requirements

Builders’ Requirements
Style, roof shape, building type: modern single-family house with garage – roof according to specifications
Basement, floors: no basement, 1.5 floors
Number of people, age: 2, 30 / 26 / 2 children desired, but twins are not unlikely due to “pre-load” → therefore a third children’s room is desired, which can otherwise be used as a playroom or ironing room
Space requirement on ground and upper floor: see design
Office: family use or home office? Yes, home office is very important
Guests per year: not relevant; guest bed/couch should be kept in the office for emergencies
Open or closed architecture: open / modern design
Conservative or modern design: modern
Open kitchen, cooking island: cooking island or half cooking island ("U-shape" desired)
Number of dining seats: 6
Fireplace: not absolutely necessary, but an option to retrofit later would be nice
Music/surround sound wall: 5.1 home cinema
Balcony, roof terrace: not necessary; but maybe a possibility to "save space" to only reach 1 full floor?
Garage, carport: garage with storage room

House Design
Who created the design:
The basis is, as mentioned, the Auro from Kern-Haus, which we then adjusted somewhat.
Important: we are open to any suggestions and do not want to force our wishes into the Auro at all costs.

Please show options that are allowed on the property. For example, a side entrance or similar would also be a conceivable option.

Please also consider the permitted extensions / bay windows / dormers. Here, 2/3 of the building length are allowed.
Do the 2/3 apply per side or overall?

What do you particularly like? Why?
The large office downstairs, which nicely faces the garden (south). In old age, a bedroom could be created here if necessary and one could live on one level.

What don’t you like? Why?
Possibly the technical and laundry room – somehow it doesn’t quite fit or what do you think?

The bathroom with the sloping ceilings doesn’t look ideal at first glance either, or is that deceptive? How could that be improved?

The hallway on the ground floor is quite huge – presumably space is wasted here. Could this be solved better?

Preferred heating technology: open

If you have to do without, which details/extensions
-can you not do without:
1. A shower on the ground floor is desired because of the dog and because of the option to be able to live on one level later.
Could the space under the stairs possibly be used to install the shower and thus gain a little more space for the utility room?
2. For the parents, a dressing room would be desirable. Ideally of course with access through the dressing room to the bedroom (so not like here)

I am aware that windows etc. are still missing in the design..

If anything is missing, just contact me

Best regards and thanks again for your great help!

For the [Auro] on the website (knee wall estimated 50cm), the following calculation results (dimensions estimated, as not measured):
Ground floor area: 7.80m * 12.00m + 2 * 4.00m * 0.80m = 100m²
Upper floor area > 2.30m: 100m² - 4 * 4.00m * 2.00m = 68m² < 75m² = 3/4 * 100m² => no full storey

Is this now just a simplified calculation or do the exterior and interior walls not play a role in the 2.3m area calculation in the upper floor?

Shower on the ground floor is desired because of the dog and because of the option to be able to live on one level later. Maybe the space under the stairs could be used and the shower put there

Dog yes, age no: at 30/26 you will almost certainly be among those who build new homes near retirement age – the trend among those now in their late fifties will have caught you by then. I will take a look later to find the discussion(s) about shower standing height under the stairs.

Do the exterior and interior walls not count in the 2.3m area calculation in the attic?

As far as I know, no: "including their enclosing walls".

Dog yes, age no: at 30/26 you will almost certainly be among those who build new homes close to retirement - the trend among those now in their late fifties will have caught up with you by then. I'll check later where I can find the discussion(s) about the shower standing height under the stairs.

Okay, yes - building again or moving into a condominium or something similar at an older age is definitely not out of the question.
Nevertheless, we find the shower useful - dog, possibly the office as a "teenager" room at some point, or also currently for visitors (which, to be honest, is limited). Primarily for the dog.