New roof windows - wording in the development plan

Hello everyone,

we live in a two-family house with 2 full floors (1st living unit) and a converted attic. (2nd living unit)
Our apartment in the attic extends over two levels, with a gallery and an adjacent room upstairs. The gallery counts as living space, the adjacent room officially only as usable space.

Now we would like to have more roof windows installed on the upper level to make it a bit brighter and to enjoy the view of the forest.
At a later stage, we would like to apply for a change of use for the room.

There is a development plan that stipulates the following:

"In all areas, roof windows at different heights are excluded.
Roof windows are to be limited to 0.75 m in width and 1.50 m in height.
The sum of all roof window widths must not exceed 25% of the respective eaves length.
Stacking roof windows one above the other is excluded."

The eaves length is 9.60 m, so we are allowed a total window width of 2.4 m.

Now to the questions.

- What exactly is meant by the first sentence? Must the bottom edge of all roof windows be at the same height?
- Is the width specified in the development plan the total width of the window? For example, if I look at the window manufacturer V, only 0.66 m would be possible since the next larger width is already 0.78 m. Correct?
- For the 2nd escape route for the change of use, we need 0.9 m clear width. According to the development plan, this is not possible. In the documents of the previous owner, a change of use was already considered in 2001. At that time, there was also a building permit for the conversion. However, it was not carried out. Does this mean approval can also deviate from the development plan? Or was it different then than today?
- Is it possible to deviate slightly from the 2.4 m width? For example, if it would end up being 2.46 m?

I hope I was able to express everything somewhat understandably. All this stuff with building regulations etc. is just too much for me...

I'll give it a try with my forum knowledge :)

What exactly is meant by the first sentence? Do the bottom edges of all roof windows have to be at the same height?

Yes, they basically have to be lined up with spacing.

For example, when I look around with V at the window manufacturer, a maximum of 0.66 m would be possible, since the next higher width is already 0.78 m. Correct?

Correct.

For the 2nd escape route for the change of use, we need 0.9 m clear width. However, this is not possible according to the development plan.

Back then there was also a building permit for the conversion. However, it was not implemented. So it is possible to deviate from the development plan with a permit?

That depends: did the previous owner perhaps plan a window for the conversion into living rooms in the gable?
Otherwise, it is quite possible if the conversion brings a higher quality of living. Building authorities are not troublemakers after all ;)

Is it possible to slightly deviate from the 2.4 m width? I.e., if it would end up being 2.46 m, for example?

Here I also think: yes. Up to 10% deviation is often quite tolerated and then approved.

a maximum of 0.66 m would be possible, since the next larger width is already 0.78 m.

66 cm is quite narrow though. Are there no other manufacturers with different dimensions?