Governing Vertical Urbanism: Property Rights, 3D Land Administration and the Sustainability of Inter-Building Connectivity

Sustainable Development Goal 11 makes vertical intensification a primary way to reconcile urban growth with finite land, but its land-saving promise depends on inter-building connectivity, and that is what conventional land administration cannot govern. Organized around two-dimensional cadastres and horizontally bounded property rights, existing frameworks cannot handle the overlapping volumetric claims, shared liabilities, and cross-boundary access obligations that connected vertical development generates. We treat this as a land governance problem, using the term block city for an urban configuration coordinated across vertical levels. Combining a framework grounded in socio-technical transitions and urban governance with comparative analysis of Singapore, Hong Kong, Japan, and Buenos Aires, and a regulatory analysis of Chile, we show that the degree of vertical integration tracks the structure of land tenure: a coordinating land-rights condition is necessary, and a registrable volumetric right alone is not sufficient, as Buenos Aires shows. In Chile the barrier is institutional rather than technical, and the same gaps leave SDG Indicator 11.3.1 blind to the land that vertical intensification saves. The same reforms that would enable inter-building connectivity would make its sustainability contribution measurable. The block city is best understood not as a design typology but as a contingent institutional trajectory, whose realization depends on whether land governance can manage interdependence across property boundaries.