The transition towards circular practices in the construction sector requires integrated approaches addressing both material resource procurement and the fragmentation of local stakeholder networks. This study presents the ACT-FLOW Framework, a multi-level approach enabling territorial circular processes by integrating actor networks and material flows. The framework comprises three interconnected levels (strategies, processes, and indicators) supporting the definition, implementation, and evaluation of circular practices across building and territorial scales with an iterative refinement phase. Methodologically, it was developed through a Design Science Research approach (DSR) articulated into four steps: (1) define the scope and boundaries; (2) develop a knowledge base; (3) structure the framework and its components; and (4) validate and apply it to a real case, the Circular Design Polito Lab, a research infrastructure currently under development by the Politecnico di Torino (Italy). The results demonstrate how the framework supports stakeholder coordination, structures circular workflows, and enhances circular performance monitoring. The primary limitation is that the case study has not yet been realized; consequently, it is not feasible to conduct an ex post but only an ex ante evaluation of the results. Future research will assess the framework’s capacity to foster ecosystemic conditions for circular construction practices through its longitudinal application across project phases.

The construction sector generates over one-third of all waste in Europe, yet the reuse of building components remains marginal compared to recycling, and circular strategies are rarely aligned on the territorial scale at which materials, stakeholders and infrastructure operate. This paper investigates the regulatory, institutional, infrastructural and operational conditions under which reuse to become a systemic practice. A desk-based comparative analysis of six European contexts (Belgium, the Netherlands, Switzerland, Germany, France, Denmark) was conducted on 282 documents, using a framework of seven dimensions grouped into three macro-families drawn from the literature on territorial circular ecosystems. The findings show that these conditions form a dependency chain of five ordered links: legal recognition of the non-waste status; a standardized pre-demolition audit; preparation and storage physical hubs, in parallel with research infrastructures, absorbing technical uncertainty; a guarantee system covering performance, liability and insurability; and a demand-side activation. The guarantee link is a constraint and a key element in demand activation. Regulation is necessary but not sufficient, since binding instruments target recycling or auditing while reuse remains voluntary in all six contexts. The chain yields a typology of ecosystem configurations and a replicable diagnostic instrument, whose transferability is assessed on the Italian case.