Expansion/Modification of Entrance Area

In an existing building (single-family house) within the scope of the BayBO, a single-storey extension / enlargement of the entrance area is planned on the east side as part of renovation measures, for which the 16m privilege applies (see attached plan). This leads to an extension up to a distance of 2.4 m to the neighboring property, with the subsequent necessity of registering a distance area transfer by the neighbor. Are there possibilities to execute this extension as a subordinate component or could it possibly even be considered a subordinate component?
Regarding the plan, it should be noted that the house has a length (north/south) of 12.3 m, the lower wall on the east side opposite the construction boundary (i.e. external wall 1st floor) in the north is slightly (approx. 0.2 m) and in the south more strongly (i.e. 1.5 m = current covered entrance area) recessed. The orientation in the illustration is north at the top, south at the bottom. The distance of the house (without extension) from the eastern property boundary is 4.2 m on the ground floor and 4 m on the 1st floor.

BayBo Art.6 Para. 6

When measuring the setback areas, the following are disregarded:
subordinate projections such as balconies and single-story bay windows, if they
a) overall do not occupy more than one third of the width of the exterior wall of the respective building, at most 5 m each,
b) do not protrude more than 1.50 m beyond this exterior wall and
c) remain at least 2 m away from the opposite neighboring boundary

So, in your case, in my opinion, it is not the 12.3 m that counts but only up to the recess, the (12.3 m - 2.60 m) 9.7 m (an architect once explained this to me, I didn’t want to believe it either and am still not convinced).
9.7 m x 1/3 = 3.23 m. From the plan I see that your extension is about 4.4 m long --> not possible!
Maybe the building authority would accept the entire house length as reference, so 12.3 m * 1/3 = 4.1 m --> also not possible!
Your extension may therefore, depending on the interpretation of the definition of "exterior wall," only be either 3.23 m or 4.1 m long.
Furthermore, it may be a maximum of 1.5 m wide (measurement not given in the drawing). And the extension/bay window may be at most one story high, so it may not be continued in the attic, e.g., as a dormer.



This way you could achieve an extension of 4.1 m without major discussion. (WC window then to the side and giving the room there a bit more space)

should not be a problem after some changes.

Slightly shorten the bay window, reduce wall thicknesses.

Quote BayBO 2021 setback areas:

"2.
subordinate projections such as balconies and single-storey bay windows, if they
a)
in total do not occupy more than one third of the width of the exterior wall of the respective building, at most 5 m each,
b)
do not project more than 1.50 m beyond this exterior wall, and
c)
remain at least 2 m from the opposite neighboring boundary,"

How far does the bay window project? Unfortunately, it is not dimensioned.

Thank you very much for the answers. To clarify the inquiries: The extension is planned as a single storey; according to the current plan, it projects on the ground floor by 4.2 m - 2.43 m = 1.8 m in front of the wall, compared to the external dimensions of the entire house (which are reached on the first floor and roof) by 4.0 - 2.43 m = 1.6 m. Attached is another picture to clarify the matter a bit more. My question was also whether anyone has experience if a main entrance area can even be considered a subordinate component within the meaning of the regulation (i.e., clearly no bay window and no balcony).

"Neighbor thread" reading tip:

whether a main entrance area can even be a subordinate component within the meaning of the regulation (i.e. clearly not a bay window and not a balcony)

From a construction standpoint, it is a bay window. Whether you have a sofa, a bathtub, or a shoe cabinet inside is initially irrelevant.

However, two problems arise here:
1) 1.6m is < 1.5m maximum permissible depth
2) As the ground floor exterior wall is currently, 4.3m is significantly more than max. 1/3 of the wall (even if the house is a total of 12m long)

These projections are called "subordinate components" because a maximum of 1/3 of the wall length is considered subordinate, meaning the original wall is still recognizable as the decisive one despite the bay window. With a further recess as in your case, this is no longer given.

If it is "only" about a guest toilet in this area, build it as a bay window, 3m length would suffice there as well ;-)