The lifecycle phase in which the technical experts (e.g. designers and engineers) define key features, success criteria, and major deliverables of the project, thereby specifying the Concept Design and preparing the project for construction. Key deliverables include design and construction documents such as plans, structure calculations, and material specifications as well as the preliminary contract document package. Importantly, detailed sustainability considerations like the carbon footprint of the materials used or specific mitigation measures to address social and environmental impacts should be incorporated into a project’s Detailed Design.