Development plan - 1.5-story building?

It would be interesting to know whether the development plan specifies an eaves height. If it is, for example, 4m, you have a knee wall of max. about 75cm. A city villa has a minimum eaves height of 5m...

Hello. What about a knee wall if the maximum wall height in the development plan is specified as 4.5 meters? The building height starts from the same lower reference point and ends at the uppermost roof edge. The wall height of single-family houses is measured in the middle of the building; for semi-detached houses, the reference point at the boundary between the two halves of the building is decisive. For single-story buildings, a maximum wall height of 4.50 m is set. Subordinate components (projections, staircases, etc.) whose total does not exceed one third of the building width may exceed this dimension. However, the height of the subordinate components must not exceed 6.50 m. In the area of the specified single-story, the building height must not exceed 9.00 m in any case. This is what is stated in the development plan. But nothing about eaves height.

The eaves will probably have to be below 4.50m. It is simply a different reference point.

If you build without an overhang, the eaves height = wall height.

The eaves will probably have to be below 4.50m. It's just a different reference point.

If you build without an overhanging roof, the eaves height = wall height.

Ok. And how would that then affect the knee wall? The development plan says nothing about eaves height.

The development plan says nothing about eaves height.

As my predecessor already explained, it won’t be there either – either eaves height or wall height, you don’t need the same information twice with a slightly shifted reference point.

And how would that affect the knee wall then?

Your reference height in the terrain plays a major role in how much of the wall height remains for the knee wall. From the wall height, you have to subtract the story height of the ground floor, the floor construction in the upper floor, and the difference between the ground floor slab height and the terrain reference height. Your story height is 2.85 m, the floor construction in the upper floor is 12 cm, and the terrain reference point is 68 cm below the ground floor slab; then 85 cm remain of the 4.50 m for the knee wall.

Given a maximum wall height and ground level, the knee wall essentially depends on the roof pitch and wall thickness. The roof thickness is mathematically irrelevant. The rest is in theory just a bit of geometry, and in practice a bit of architecture as well.

Example:

450cm wall height, 40cm wall thickness, 45° roof pitch, interior wall height 490cm

Ground level is equal to the top edge of the floor slab, meaning a step into the ground floor.

15cm ground floor flooring
250cm ground floor
20cm ground floor ceiling
15cm upper floor flooring
= 300cm

You have 190cm left for the knee wall on the upper floor, maybe 185cm with the interior roof finish.

However, you will run into the problem that, mathematically, you likely have a two-story building. So you will have to choose a lower knee wall anyway. Or you let the basement protrude out of the ground, which you will of course have to subtract above as well. Just like the loss due to a lower roof pitch.