Large amounts of energy and resources are consumed in construction industry and have great impact on environment. Current studies suggest that total CO2 emissions due to the construction sector account for 8% of the global total emissions. Several studies have therefore investigated the environmental comparability of structures according to the material used. For instance, in some cases there is evidence of a 17.47% increase in CO2 emissions between alternatives for the same structure. Due to generation of this data, more sustainable structures can be designed. For this purpose, several alternatives were generated by modifying structural parameters such as floor slab typology, distance between pillars, material of the vaults in a specific case of study. The methodology used was through the specific structural calculation program such as CYPE, in which reinforced concrete and metallic structures can be modelled. Subsequently, environmental studies were obtained from the various alternatives generated through the life cycle analysis (LCA) of each alternative. The field of study of LCA was from the production of the necessary elements to their implementation in the structure. In this way, it is possible to give the project a more global image of the impacts it generates, not only in economic but also in environmental terms. Some of the results obtained show that the use of a type of floor slab with certain characteristics compared to another type of floor slab represents an increase of approximately 17% in the kg of CO2 equivalent emitted. Emissions are also influenced by the use of the vault material. On average, the expanded polystyrene vaults reduce CO2 emissions by 5.31%, as the loads to be transmitted are reduced because the use of lightweight vaults means less load on other structural elements and therefore less use of concrete. As a result, alternatives with more environmentally friendly characteristics are obtained and more sustainable buildings are designed.