Associations have been labelled the main ‘building blocks’ for creating social capital. It has been argued that community associations need to transform ‘bonding’ into ‘bridging’ ties to ‘reach out’ while also creating ‘linking’ ties to ‘scale up’. External development actions follow a reverse logic in promoting these associations: they assume that linking ties with the external intervener will reinforce prior social capital endowments. This article highlights the inherent difficulties of such a ‘social engineering’ approach in the context of post-conflict reconstruction, describing three development interventions in the north of Burundi. It defines the process of ‘institutional syncretism’ – merging local with global institutional settings – as a key element to social capital building. The findings illustrate how the three interventions failed to reach this objective, and question ‘bridging’ associations as ‘universal blueprints’ for restoring social cohesion within the liberal peace model for post-conflict reconstruction.