The role of intermediaries in the adoption of innovative building materials: Insights from the case of clay building panels in Germany

Abstract

Material choices in residential construction rarely result from a single decision. They emerge from a sequence of prior commitments, professional routines, and actor constellations that progressively constrain what is feasible long before a homeowner approves anything. This paper examines how innovative building materials move through, or get filtered out of, small-scale construction and renovation projects, using clay building panels in Germany as a case. Drawing on fifteen qualitative expert interviews with architects, tradespeople, retailers, wholesalers, and manufacturers, the study traces material decision-making as a path-dependent, multi-actor process. Two functional groups of intermediaries are identified: planning-oriented intermediaries shape the solution space early by fixing construction systems and specifications; execution-oriented intermediaries exert influence closer to installation, guided by workability, liability, supplier relationships, and cost. Both groups operate as gatekeepers, but at different stages and through different logics. Much of this filtering remains invisible to clients. The article frames innovative building materials as credence-like goods whose adoption depends more on intermediary trust and professional habit than on homeowner evaluation. The findings offer implications for manufacturers, intermediary-focused policy instruments, and for research on sustainability transitions in construction.