The maximum height of the knee wall, everyone says something different.

Dear members of the house building forum,

this concerns the maximum permitted height of the knee wall which is to be considered realistic. We have approached different providers of prefabricated houses as well as an architect, who sells solid houses for another company, with the development plan. Each has given us different heights based on the provided information. I mean the actual height after construction, measured inside. So when I enter the finished house and hold the measuring tape against the wall.

Attached are the key data and excerpts from the development plan:
I Floor area ratio 0.3
o Plot ratio 0.3
SD 30-45 degrees
SHüS2: 0.5 m
FHüS2: 9 m

I would appreciate a further assessment and am curious, maybe there is a logical explanation why some say 90 cm (solid house provider) and 1.20 m (prefabricated house provider). Is it due to the construction method or the inexperience of the salespeople?

Here are a few more details from the development plan:
0.1 ROOFS
10.1.1 In the planning area, depending on the designation in the plan drawing, gable roofs (SD), shed roofs (PD) or flat roofs (FD) are permitted. Gable roofs may be hipped (full hip, half-hip, pyramid roof).
10.1.2 Unless otherwise specified below, roofs are to be executed with red to red-brown, gray or anthracite-colored clay or concrete tile coverings. Roof coverings must not have reflective surfaces. Green roofs are also permitted. On buildings with more than 2 residential units as well as in the areas WA(S) and the area for community needs (KiTa), green roofs are mandatory if the roof pitch is less than 20 degrees. On buildings with more than 2 residential units, full floors may be covered up to a maximum of 25% by terraces and green flat roofs.
10.1.3 Roofs of ancillary buildings and garages may, contrary to points 10.1.1-10.1.2, have gable and shed roofs with roof pitches from 0 to 45 degrees. Roofs of ancillary buildings with ground areas of more than 6 m² and of garages must be greened.
10.1.4 The width of dormers, roof loggias and roof windows may measure a maximum of 33% of the eaves width per side. They must maintain at least 1 m distance from the ridge and at least 2 m from the verge, measured in the roof slope.
10.1.5 Throughout the planning area, large, non-reflective solar systems arranged in the roof pitch (solar thermal and photovoltaic) are permitted. They may cover a maximum of 70% of a roof area and must maintain a minimum distance of 1 m from eaves, verges and ridges, measured in the roof pitch.
10.2 FACADES / WALLS / ANCILLARY BUILDINGS / GARAGES
10.2.1 The facades of the main building bodies in the planning area are to be designed with bricks, bricks, plaster or other materials in light red, red to red-brown tones.
10.2.2 For a maximum of 30% of the respective facade area of a main building body as well as for ancillary buildings, privacy walls and garage and carport exterior walls, surfaces of other materials in the colors red, red-brown and beige as well as in off-white and gray are permitted.
10.2.3 Garages and carports must be built at a minimum distance of 3 m from street boundaries.

Attached are the key figures and excerpts from the development plan: I floor area ratio 0.3 o floor space index 0.3 SD 30-45 degrees SHüS2: 0.5 m FHüS2: 9m

It’s best if you name the development plan (not as a link! / e.g. in the format "Posemuckel No. 234 Wiesengrund II"). I’m guessing that it specifies a reference height called S2, where the maximum base and ridge heights are allowed to be. Eight and a half meters of house height in between sounds seemingly generous, but identical floor area ratio and floor space index at 0.3 suggest that the “I” full floor is taken very seriously. In my mind’s eye, I see a steep gable roof with a lot of Drempel and little to no Kniestock.

It’s best if you just name the development plan (not as a link! / e.g. in the format "Posemuckel Nr. 234 Wiesengrund II"). I’ll speculate that it specifies a reference height called S2, which sets the maximum allowed base and ridge heights. Eight and a half meters of house height in between sounds supposedly generous, but identical floor area ratio and plot ratio of 0.3 suggest that the "I" full story is meant very seriously. In my mind’s eye, a steep gable roof with lots of knee wall and little to no knee plate appears.

Thank you very much for your quick response! It’s really great when a community is so active. I hope we’ll have a great exchange here in the future.
Now, about the building project: yes, they really do take the I full story seriously; the question is simply, what can we effectively get out of the first floor. Please enter this into Google: Schönberg-Bebauungsplan-67-vorläufiger-Rechtsplan.pdf
Thanks for your effort!

Please enter in Google: Schönberg-Bebauungsplan-67-vorläufiger-Rechtsplan.pdf

But now I certainly should not compare all thirty sections of the development plan with your details from the usage template. Please insert a snippet here where the property can be identified.

Yes, they really mean business with the I full floor, the question is simply, what can we effectively get out of the 1st upper floor.

The upper floor will definitely be an attic floor. Keep in mind that it is better to optimize the knee wall rather than maximize it! It may be wiser – especially since the "I" will not be negotiable here – to come to terms with a knee wall instead of possibly combining knee wall and dormer one after the other (except possibly partially, e.g. in the bathroom).

I am not supposed to cross-check all thirty sections of the development plan with your usage template data. Please insert a snippet here where the property becomes identifiable.

The upper floor will definitely be an attic. Keep in mind that it is better to optimize the knee wall rather than maximize it! It may be wiser—especially since "I" won't be negotiable here—to come to terms with a short wall instead of possibly combining a knee wall and a short wall consecutively (except possibly partially, e.g., in the bathroom).

I understand, a short wall is not really what we currently envision, let’s see if we can still come to terms with it. But a knee wall would be desirable. With the floor area ratio, one is limited. The goal is that not 50% of the rooms upstairs have a ceiling height under 2.20 m.

Attached is the image

The floor area ratio is limited, after all.

No, the floor area ratio alone does not impose the limitation, the site coverage ratio and floor area ratio each at 0.3 are merely maximum values. If it were only based on those, a "city villa" would be possible with an actually utilized site coverage ratio of 0.15. There is no eaves height restriction here, so for a building height of 9.00 m only the "I" full floor stands in the way, since a 30° gable roof could possibly still start above the upper floor ceiling. According to your screenshot the case is clear: the reference height is 7.99 meters, so the base height is at most 8.49 meters and the ridge height at 16.99 meters. In terms of height, I see the greatest limitation in the partial floor. My bigger concern would be the trees and the two parking spaces.