The present study discussed the significant environmental impacts of a residential building located in New Cairo, Egypt. This covered all life cycle steps from cradle to cradle with a projected 60-year life span: (i) an inventory of all the construction materials were analysed, covering the building structure as well as the energy consumption; (ii) three types of functional units were defined; (iii) the two top building materials were examined, and a sensitivity analysis was conducted to investigate the impact associated with the choice of building materials. The result shows that two life cycle phases concerning, manufacturing and operation, were more significant in all of the impact categories. It also shows that building structure and flooring result in most of the environmental loads. In terms of the sensitivity analysis, it was found the structural concrete had the largest impact, dominating all selected impact categories except ODP. Finally, limitations and challenges are discussed to explore better design decisions for selecting buildings’ structural systems in future studies.