The examination of the environmental impact of buildings during the design process is becoming increasingly important nowadays. Since the geometry and materials of the building are chosen during the conceptual design phase, it is of paramount importance to explore alternative solutions during this stage, considering their significant effect on the building’s environmental footprint and performance later. The aim of this study is to compare the environmental impact of an industrial hall depending on the applied structural material and geometry. 48 different geometries were generated and evaluated using parametric design focusing on the first stage of the lifecycle. Regarding the material of the load-bearing structure, the prefabricated reinforced concrete hall exhibits a lower overall environmental impact compared to the steel structure of the same geometry. In terms of geometry, among the three spans examined (16.5, 18, and 20 meters), the largest span proves to be the most environmentally advantageous.