ᐅ Single-Story Construction – Is It Possible to Include a Dormer in the Upper Floor?

Hello,
I hope it’s okay that I’m starting a new topic here (I had already opened a similar one, but now it’s getting more specific).

Does anyone have experience with whether it is possible, in terms of dimensions, to install a dormer on the upper floor in a single-story building?
I want to achieve more usable space with vertical walls instead of sloped ones.

The building is located in Schleswig-Holstein, and the building regulations state:
Full stories are above-ground floors that have at least three quarters of their floor area with a height of at least 2.30 m (7 ft 7 in). A top floor set back from at least one exterior wall of the building or a floor with at least one sloped roof surface counts as a full story if at least three quarters of the floor area of the floor below have a height of at least 2.30 m (7 ft 7 in); the height of the floors is measured from the top edge of the floor slab to the top edge of the floor slab of the ceiling above, or for floors with roof surfaces up to the top edge of the roof covering.

The definition is clear, but is this possible with a single-story structure?
Google didn’t help much when searching for “single-story with dormer.” A floor plan would be especially helpful.

Thank you very much.

Typically, a dormer creates a standing height of 2m (6.6 feet) or more—meaning a fully counted floor area within the room—whereas without it, the height would usually be between 1 and 2m (3.3 and 6.6 feet), which counts only as half the floor area. In this way, the dormer effectively "increases" the usable floor space in the attic and contributes to how close the area comes to being considered a full story.

A second reason to use dormers sparingly is that building regulations for roof pitch, eaves height, and so on often include limits. For example, only up to one-third of the roof length may be covered with structures like dormers.

arbeiter01 schrieb:
Here, I want to achieve more space with straight walls instead of sloping ones.

What I wrote above also applies to cross-gabled dormers (Zwerchhäuser), which you probably mean here: these are related to dormers but have fronts that continue straight from the facade instead of being inserted within the roof surface.

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Purely a calculation example!
Basically, a single-story design does not exclude one or even two dormers.

Thank you,
I will need to calculate that then.

I have a question regarding the calculation of floor areas:
From 2 m (6.6 ft) ceiling height, 100% counts as floor area,
from 1.5 to 2 m (4.9 to 6.6 ft) ceiling height, only 50% counts,
below 1.5 m (4.9 ft) it is not counted at all?
Is this correct?
Where can I find this information? In the building permit / planning permission? In the construction contract? Or in the state building code?

Thank you very much

arbeiter01 schrieb:
Thank you very much,
I will have to calculate that myself then.

I have a question regarding the area calculation:
From a ceiling height of 2 m (6.6 ft) upwards, 100% is counted as area,
from 1.5 to 2 m (4.9 to 6.6 ft) ceiling height, only 50% is counted,
under 1.5 m (4.9 ft) is not counted at all?
Is this correct?
Where can I find this information? In the zoning plan? In the building contract? Or in the state building code?

Thank you

This concerns living area calculation, not full storey calculation.
You have quoted or written what defines a full storey yourself above.

arbeiter01 schrieb:
From 1.5 to 2 m ceiling height, only 50% counts

No, between 1.0 and 2.0 m (3.3 and 6.6 ft) it is counted as half.

For the calculation of full storeys, it can be much more important in which range 2.3 m (7.5 ft) is met – you need to check the respective state building code. As you cited in your example above, this concerns storey height, not room height.

For the floor area ratio (FAR), however, the calculation method for living space is relevant, so it’s best to keep that in mind consistently. If you want to maximize the last allowed cubic meter, you end up calculating longer than you build.

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