Definition of a full storey in Mecklenburg-Vorpommern

I'll give you a sketch, we discussed the topic recently. The 2.30 is measured in Hesse from the top of the unfinished floor to the top of the rafters.

I’ll come back later and think of a simpler calculation and way to understand it.

Here I am again. So, let’s not start with the number crunching, but with the logic. The areas at the top and bottom are affected by the same factor, namely the house length / ridge length. Being "like terms," we can cancel out this dimension in our logical consideration, which makes it clearer. At the top (in the area to be accounted for), we should have a maximum of two-thirds of the bottom value. So we have to get rid of one-third, i.e., remove it from the relevant area (between the two 230 height lines). Into this Nirvana account we can already book the eaves-side exterior wall thicknesses in advance, because whenever the knee wall is lower than 230, they always lie entirely in the "under 230" area. Now we still have to remove the area between the 230 height lines and the interior edges of the exterior walls. We assume a symmetrical gable roof and, for simplicity, consider only half the house width (between ridge plumb line and eaves). Our house width is 905 cm in the example, half is therefore 452.5 cm. Of this, only two-thirds may remain in the accounted area, consequently we have to shift one-third (here 150.83 cm) into the Nirvana area. We have borrowed 46.5 cm (the exterior wall thickness) here, so we still need to work out 104.33 cm. This is now our target value for the length of the adjacent side. Now, as lazy people, we ask our scientific calculator what the tangent factor would be. For 45° pitch it is 1.00. We thus have to subtract 1.00 × 104.33 cm from 230 cm in order not to exceed the two-thirds measuring rod. Consequently, our knee wall is at most 125.66 cm high. We see: that is less than the desired 140 cm. Now we can consider which strategy to pick, i.e., which of the two incompatible factors we sacrifice in order to meet our specification. The knee wall height is usually more sacred to home builders than the roof pitch: so let’s fix the knee wall height at 140 cm. That is 90 cm below 230 cm. 90 to 104.33 is 0.8626. We ask the calculator oracle again: this tangent factor corresponds to a pitch of 40.78° - even a bit more than the 38° from Yvonne’s proposal, which I had roughly guessed as the target range. If old 11ant miscalculated late at night, then feel free to be Schadenfreude - otherwise the calculation method should now be clear.

Thank you for explaining the calculation process. That is understandable. We are only still wondering why our architect’s view is different. She is employed by the construction company we are building with, and hundreds of houses are planned and submitted every year. She says they have never had problems with their approach. Only our gut feeling is leaning towards your direction, , which is why we have some trouble "trusting" the architect. We fear that our building application might not be approved.

Thank you very much @11ant for presenting the calculation method. That is understandable.

I am very pleased about that – often one encounters disappointment when trying to explain calculation methods in principle, many people prefer numerical examples.

We are only still wondering why our architect's view is different. She is employed by the construction company we are building with, and hundreds of houses are planned and submitted every year. She says they have never had problems with their approach.
Only our gut feeling goes in your direction, @11ant, which is why we have some trouble “trusting” the architect. We fear that our building application will not be approved.

The planner knows more concrete details about the object. It does play a significant role where exactly – see explanation by in post #7 – a measurement is to be taken; and also the type of individual rooms (storage rooms vs. living rooms for example) can influence the overall calculation in detail. And finally: if it is approved and they miscalculated unnoticed by the building authority – so what. In case of doubt, the stamp remedies that. If a jealous neighbor recalculates and complains, there will be no building stop over two square meters. For that, there is the good old principle of proportionality. But I consider it more likely that we are both right and she knows a few more details of the specific individual case that add a bonus into the overall calculation.

I have to say, my sketch was designed for a house 10m wide and 0.75x full floor. I'm surprised that there are state building regulations where 0.66 is required.

Oh well, the distances between 75% up to the top edge of the rafters and 66% clear dimensions are not that large after all. And hiding behind federalism with inconsistent "state competence" regulations is a popular argument within the EU to claim that the wishes of citizens cannot be implemented "unilaterally at the national level." I love the Bremen cable car law *LOL*