This architectural thesis can be understood as the report of an exploration of sustainability, participation and the building life cycle. Against the background of changing societies and our planet’s changing climate, the project presented deals with the various aspects of sustainability, and tries to envision a democratic and sustainable design process supported by technology. To identify the goal and purpose for the project, a participatory design process with a co-housing group in Austria was performed to detect the group’s common vision and requirements towards a residential project. Through several workshops these were elaborated and shaped into first conceptual designs. To assess and improve the environmental performance of these concepts and support fact-based design decisions, a variety of scenarios for building materialisation, energy standard and energy supply mix were compared using the method of Life Cycle Assessment (LCA). Working towards the integration of LCA into the architectural design and planning process, a prototypical workflow to combine LCA with the planning method of Building Information Modelling (BIM) was developed. Through the application of visual scripting, essential steps of LCA could be integrated into a BIM workflow and novel methods of communicating assessment results using the digital building model could be shown.