Abstract Like any persistent challenge, the transition from a linear to a circular construction economy requires systemic changes. To divert from current practices that maintain the take-make-waste logic, we need new ways of doing and thinking within the value network of construction. In search for those enduring changes, a compass group advises the Flemish Living Lab on Circular Construction. This lab is a three-and-a-half-year project of study and experiment initiated by policy. During four participatory workshops, the compass group identified the most important system hurdles and necessary changes for achieving a circular construction economy, through subsequent steps of system analysis, translation and reflection. These outcomes have been synthesized and validated during the last workshop and are presented in this paper as a preliminary outcome of lab. Further, by bringing together forerunners of construction and co-creating together new knowledge, it is demonstrated how a well-guided compass group allows to bring into practice ‘participatory system modelling’. By consequently translating the resulting insights into the requirements for a targeted call for experiments, it is finally shown that this co-created knowledge has been ‘actionable’ for the policy makers of Circular Flanders, and triggered dozens of partnerships to submit an experiment.