Proof of single-story construction - How is this calculated?

Hello everyone,
how exactly is the calculation for proving single-story status done?
I know about the 2/3 area relative to the ground floor... and the height of 2.3m on the upper floor, etc...
Specifically, I am interested in the following:
Does the covered terrace need to be included in the ground floor area if it is only enclosed on 2 sides? Or is only the area enclosed on three sides considered?

We are planning a covered terrace on the ground floor. In one corner of the house, the walls are recessed. As a result, only 2 sides of the roofing are closed. Does this also count towards the ground floor area?

To help you visualize better, I have uploaded the plan of the ground floor.

We are planning the construction in Hesse.

Thank you very much and see you soon.

I know the thing with 2/3 area

In Hesse, it is 3/4. §2 (4) HBO Full floors are above-ground floors that have a height of at least 2.30 m. 4 A top floor (set back from at least one exterior wall of the building, a recessed top floor) and a floor with at least one sloping roof surface is a full floor if it has this height over more than three quarters of the gross floor area of the floor below.

and the thing with the height of 2.3m on the upper floor

5 The height of the floors is measured from the top edge of the raw floor slab to the top edge of the raw floor slab of the ceiling above, in floors with roof surfaces to the top edge of the supporting structure. So neither the clear height nor the outer edge of the roof covering is meant , but the top edge of the rafters.

Does that also count towards the area of the ground floor?

I think yes. Recommendations for the implementation of the HBO 2011 (HE-HBO) 2.3.3 ... Floors are horizontal building sections lying on one level, which are usually separated from each other by ceilings. The ceiling can also be a roof surface at the same time. Exterior walls are not required. ... 2.2.4 The term “gross floor area” refers to the calculation method regulated in DIN 277 Part 1. ... see also Wikipedia: Grundfläche: Architektur

Great. Thanks for the quick response. I hope the building authority sees it the same way. What surprised me was that the 2.3m limit is measured from the top edge of the rough floor and not from the top edge of the finished floor. How is the top edge of the load-bearing structure determined? What thickness of the roof rafters is assumed there? The 1m and 2m limits shown in the plan – is that the clear dimension from the top edge of the finished floor to the underside of the roof structure?

I hope the building authority sees it the same way.

Will it still be tight despite the 3/4?

How is the upper edge of the supporting structure determined?

Recommendations for the enforcement of HBO 2011 (HE-HBO) 2.4.5 With the amendment of 25.11.2010, the upper reference for the calculation of full storey height for floors with roof surfaces was changed: the upper edge of the supporting structure is now decisive. Due to the amendment, the roof covering as well as thermal insulation applied on the supporting structure are not credited.

What thickness of the roof rafters is assumed?

Why assumed? Your planner should know which dimensions he has to build with.

Is the 1m and 2m limit shown in the plan the clear measurement from the upper edge of the finished floor to the lower edge of the roof structure?

Yes. I have not seen a plan with these limits, but usually that is the case, since these lines serve the calculation of living space.