The construction sector is one of the most polluting industries, generating between 30% and 40% of the worldwide environmental burden in terms of raw materials, direct and indirect energy consumption, waste, and CO₂ emissions. Recent advances in computer science and data management have facilitated the evaluation of present and future impacts, thus improving the sustainability of architectural designs. Powerful software tools, such as Building Information Modelling (BIM), allow environmental indicators to be incorporated into the construction elements that make up the project to evaluate it during the design stage. In this work, the state of the art of ecological indicator application through BIM platforms is studied. Barriers and uncertainties are also identified. Subsequently, a model is proposed to evaluate the environmental impact of an urbanization process or a project through several ecological indicators (carbon footprint, water footprint, and embodied energy). To perform this analysis, the most important aspect is to determine the quantities of each construction element and their clear decomposition into subelements, since both aspects add certainty to the analysis. For this purpose, construction cost databases are a good instrument for introducing environmental awareness. The reliability of LCA data, which can be obtained from generic databases or ecolabels such as environmental product declarations, becomes crucial.

Existing tools for environmental certification of buildings are failing in their ability to reach the general public and to create social awareness, since they require not only specialized knowledge regarding construction and energy sources, but also environmental knowledge. In this paper, an open-source online tool for the estimation of the carbon footprint of residential buildings by non-specialized users is presented as a product from the OERCO2 Erasmus + project. The internal calculations, data management and operation of this tool are extensively explained. The ten most common building typologies built in the last decade in Spain are analysed by using the OERCO2 tool, and the order of magnitude of the results is analysed by comparing them to the ranges determined by other authors. The OERCO2 tool proves itself to be reliable, with its results falling within the defined logical value ranges. Moreover, the major simplification of the interface allows non-specialized users to evaluate the sustainability of buildings. Further research is oriented towards its inclusion in other environmental certification tools and in Building Information Modeling (BIM) environments.

This publication presents a methodology for the evaluation of the water footprint of urban renewal projects. The indirect water footprint is obtained by adding together the embodied or virtual water of the materials incorporated in the 12-month project, while the direct footprint is mainly due to the green areas and rainwater collection system over its 40-year life span. The methodology, originally defined for the agricultural sector, is adapted to an urban system that includes gardens and sustainable urban drainage systems. In an innovative way, the present work analyses the amortisation of the indirect water footprint of the construction products by improvements in the city water cycle. The project involves street renewal with water-sensitive criteria, with five green areas, and road and pavement construction. The methodology identifies changes in garden designs, soil drainage, and rainwater-collecting systems in terms of blue, green, and grey water footprints. Five scenarios of a project in Seville, Spain are studied. The indirect water footprint of the project is 2.6 times higher than that in a standard project, but, due to annual savings of 65% in its direct water footprint, the breakeven point is reached in the 10th year.