The sustainability of buildings is becoming increasingly important in today's world. Ever stricter environmental regulations encourage designers to select appropriate materials and products by examining multiple alternative solutions. This article presents an analysis of the global warming potential (GWP) of the roof structure of a residential building depending on the roof shape and angle. Three different roof types (flat roof, gable roof, and shed roof) were examined with the application of commonly used composite structures. The applied range of roof angles was between 20ºand 45ºin 5-degree increments for the gable and shed roofs, while 0ºwas used for the flat roof. The analysis was conducted using the Archicad-Grasshopper live connection, which enabled rapid examination of the GWP by dynamically tracking changes in geometry and roof angle. According to the results, the roof shape constructed with a steel beam slab and a gable roof made of solid wood had the smallest environmental impact in terms of the first phase of the life cycle.