Need help with dormer / eaves / slope

Good morning.

I would need the advice of a specialist.

The following values are specified in the development plan for our property.

Roof pitch: 35-45°
Eaves height: 3.5-4.0m
Ridge height: 8.5-10.5m
Permissible number of full floors: Max I
Permissible building type: open
Permissible roof types: SD
Site coverage ratio: 0.4
Floor area ratio: 0.6

Now I would like to know if it is generally possible to build a single-family house of about 140m² footprint on this property using the max specified values, e.g. eaves height 4m, with a knee wall height of 1m in the attic? (If you design with the max height of the eaves and the ridge, doesn’t the knee wall automatically get higher as well, or am I mistaken?) We want the knee wall to be relatively high so that one can move around normally in the attic later on and possibly even plan an additional room.

And the issue with the full floor should actually not be a problem in our example, right? Since the ground floor is a full floor anyway and the first floor is under the roof and thus counts as attic and not as a full floor.

I would appreciate a professional explanation.

Thank you in advance.

Oh, one more thing I need to add, there is a dormer included on the first floor.

Hello,

And the thing with the full storey shouldn't actually be a problem in our example, right? Since the ground floor is already a full storey anyway and the first floor is under the roof, thus counts as an attic and is not a full storey.

The definition of a full storey is regulated in the building regulations of the respective federal state. In Schleswig-Holstein, for example, a storey is a full storey if it has a height of 2.30 m over at least three quarters of its floor area. Regardless of whether it is under the roof or not.

In many federal states, it is only two thirds of the floor area or a height of 2.20 m. So you have to check the building regulations of your federal state. It is actually easy to find on the internet.

Whether you are single or two storey, you can best see that by drawing a section and playing around a bit with the knee wall heights. That is, until you reach the maximum height at which your attic is no full storey.

Regards

Ok. In our case, it would then be for the state of NRW.

mh... Then probably the only way is to submit an application for a preliminary decision to the building authority and raise this request there, maybe they are willing to negotiate.