Facts

The pension foundation [B.] (building owner) received the building permit from the building authority, the Construction and Infrastructure Committee of the Bülach City Council, on 13 September 2017 for the construction of five multi-family houses with an underground garage on plot No. 8952 in Bülach. The building permit became final and binding without challenge. Disp. No. 3.6 requires approval of a construction site organisation concept before construction release.

The dispute concerned access to the construction site, in particular the use of plots Nos. 3672 and 5899 owned by [A. AG] as a construction site access. Plot No. 3672 is burdened with a right of way on foot and by vehicle in favour of parcel No. 8952.

On 30 January 2019 the building owner applied for the use of third-party land under §§ 229 et seq. PTA/ZH. On 22 January 2020 the building authority confirmed the admissibility of various uses (construction track, driving over the easement-burdened area with heavy vehicles over 7.5 t after completion of the shell, turning area, crane jib), but prohibited storage areas, excavation dumps and parking spaces of 600 m2 and 800 m2 respectively. Furthermore, a time limit of 24 months, compensation and restoration were provided for.

The Building Appeals Court of the Canton of Zurich partially upheld the appeal of [A. AG] on 10 September 2020, as the construction track was to be realised on the building plot itself as far as possible, and remitted the matter to the building authority. The Administrative Court of the Canton of Zurich dismissed the appeals of the building owner and [A. AG] on 26 August 2021.

On 22 October 2021 [A. AG] filed a civil law appeal in public law matters, alternatively an appeal in civil matters or subsidiary constitutional complaint, with the Federal Supreme Court. It requested that access for vehicles over 7.5 t be permitted via Frohburgweg or Schaffhauserstrasse and that the application for access via Unterweg and the turning area on its property be rejected. In the alternative, it requested remittal. The building owner and the Administrative Court requested dismissal. The City of Bülach waived a response. No reply was filed. The application for suspensive effect was rejected by order of 21 December 2021.

Considerations

Preliminary question of legal nature: The Federal Supreme Court leaves open whether this is a public law or civil law matter. §§ 229 et seq. PTA/ZH are based on Art. 695 CC, and according to case law (BGE 104 II 166 E. 3c) the right of hammer-blow is supplementary cantonal private law, which is why in principle the appeal in civil matters or the subsidiary constitutional complaint would be admissible. The question can remain open, as the appeal is in any event not to be entered upon.

Existence of an interlocutory decision: The Administrative Court confirmed the remittal, under which the construction site access via Schaffhauserstrasse, the construction track as well as the location and size of the turning area must be redesigned. As the building authority still has a margin of discretion, an interlocutory decision exists. The continued use of the turning area to be constructed in the 1st construction phase, whose location and size have not yet been…