This article is an investigation into how cultural debates are staged within the planning hearing for a new concert hall in Edinburgh. Through an analysis of the hearing and interviews with protagonists, it shows how the material, in this case the proposed concrete cladding, functions within a cultural controversy, providing an excellent example of how materials are socially mediated. The findings suggest that the debates over cultural impact and elitism rehearsed in the hearing are inextricably tied to two opposing ontologies of concrete, one very fixed, the other far more open. It is argued that planning hearings are an under-explored area in which cultural policy is effected, though the entwinement – indeed co-constitution – of material and cultural issues shows that the course and eventual conclusion of these debates are highly complex.