Growing concerns about environmental issues worldwide triggered the development of methodologies for assessing the impacts caused by products and systems. The construction sector is responsible for a significant amount of such impacts, thus, it is clear the need to implement measures aimed at mitigating or, at the very least, reducing to acceptable values these aggressions to the environment. This led to the application of the Life Cycle Assessment (LCA) methodology to the construction sector. This paper focuses on the environmental aspects of LCA, particularly on the indicators of embodied energy, embodied carbon and global warming potential, to compare the environmental performance of different types of buildings. Therefore, a calculation tool was developed (LCA4Building) that, upon introduction of the building materials and quantities, calculates the indicators’ values, allowing to compare the performance of the project considering these indicators, for various types of construction or alternative materials. LCA4Building was used to analyse buildings with different case study typologies. Concerning the GWP (expressed as kgCO2eq/m2), the warehouse case presented a poor performance, and the single-family housing was the one with the best performance in this indicator. The tool allowed the replacement of some materials by others, having identical structural/functional performance, reducing the impacts on categories analyzed and bringing building performance closer to more sustainable buildings. The use of LCA-based tools in the design phase can contribute to the construction of more sustainable buildings, allowing to reduce the environmental impacts, namely CO2 footprint and embodied energy.