Abstract
As marked by escalating urban crises, socio-spatial fragmentation, and environmental uncertainty, the resilience of cities increasingly depends on their capacity to foster inclusive and sustainable modes of everyday interaction. Within this context, urban in-between spaces-often overlooked or underutilized-emerge as critical arenas for nurturing social cohesion, adaptability, and continuity. This paper positions such spaces as not merely residual voids but as active socio-spatial interfaces that can significantly contribute to urban social sustainability, especially in cities grappling with the long-term effects of socio-economic instability and spatial polarization. In-between spaces function as essential socio-spatial interfaces between public, collective, and private realms, yet their contribution to everyday social sustainability remains insufficiently theorized and empirically documented. This study investigates their spatial and social potentials across three cooperative housing settlements-Tekg & uuml;l Site, Tar & imath;msal Site, and 184 Evler Site-constructed within the Ankara Bat & imath;kent Project, one of Turkey's largest participatory housing initiatives. Employing a multi-scalar morphogenetic methodology that integrates diachronic spatial mapping, typomorphological sequencing, layered interface analysis, and on-site morphological surveys, the research evaluates how intermediary spatial layers evolve over time and shape patterns of everyday social interaction. Findings indicate that the physical existence of in-between spaces alone does not ensure social sustainability. Instead, it depends on the continuity of public-space networks, spatial permeability, the preservation of collective-use layers, and sustained user participation. Conceptualizing in-between spaces as active social infrastructures, the study offers design-relevant insights for developing socially sustainable housing environments and resilient community structures.