In recent years, the claim has become mainstream that to reach ambitious environmental goals, building research can greatly profit from a transdisciplinary collaboration that crosses academic disciplines and includes non-academic partners. We summarize experiences accrued in 7 years of intensive transdisciplinary work performed in the Norwegian Research Centre on Zero Emission Buildings. Our analysis, which employs conceptual tools from symbolic interactionism (social worlds and boundary objects), is based on two surveys among the Centre’s researchers and industrial partners and eighteen qualitative interviews exploring the Centre’s members’ views and experiences. In the analysis of the material, the research centre’s eight pilot buildings emerge as boundary objects that facilitated collaboration among the non-academic partners, while ‘robust solutions’ was the main boundary object which enabled interdisciplinary academic work. Practical recommendations for transdisciplinary (building) research derived from these observations conclude the article.