Hu, MingSustainability has become a driver of innovation in the built environment, but the affordability of sustainable building remains a significant challenge, according to developers, building owners, and design teams. This dissertation proposes a framework to understand how the characteristics of a project design team are influential cost drivers. We use empirical data to understand: (1) the sustainable building construction cost (SBCC) in relation to level of sustainability; (2) the influence on the SBCC of soft cost associated with the project design team; (3) the causal relation between project characteristics, project design team characteristics and construction cost of sustainable buildings. A mixed methodology is employed with four steps: research flow; a regression model and structural equation model in the quantitative research phases; and a comparative case study in the qualitative research phase. Altogether, thirteen project and project design team characteristics are studied, and ten hypotheses tested. The findings reveal: (a) the construction cost of studied sustainable building is comparable to conventional buildings, even lower; (b) the relationship between the construction cost and level of sustainability achieved is inconclusive; (c) among the project design team characteristics, skill and experience dominate, while communication, collaboration, and innovation are less influential; and (d) technical complexity is not always related to sustainability, hence the empirical data does not proved its influence. The proposed research contributes to research and practice at three levels: data, evidence, and methodology. The broad impact of this research is to advance an understanding of the SBCC cost as a means of promoting building green. The findings and methods resulting from this research project can empower architects, engineers, and developers to promote affordable sustainable building.enDissertationCivil engineeringEnvironmental engineeringcase studyconstruction costLEED buildingsproject characteristicsproject design team characteristicstructural equation model