###### Abstract
Additional studies conducted within the EU, such as those developed by the European Commission's Task Group 4 (2003), contributed to a clearer understanding of the impact of technical decisions on the life cycle of buildings and the urban environment [14]. As a result of these efforts, unified initiatives were promoted to develop common methodologies, with limited success so far. At the outset of the 21 st century, the building stock was characterized by operational costs accounting for approximately 70% of total life-cycle costs in a context still lacking a standardized methodology to guide public organizations toward sustainable construction practices [15]. These and other trends related to the assessment of the environmental impact of human activity led to the continuous and increasingly prominent development of life-cycle assessment methodologies in Western countries, as is shown later in this study. Life-Cycle Assessment as Decision-Making Tool: Costs, Intangible Values, and ExternalitiesLife-cycle assessment (LCA) and life-cycle cost assessment (LCC) are the most known methodologies for sustainability assessment now. The application of the LCA is limited to the performance evaluation or environmental sustainability of an activity or product, while that of the LCC is limited to the performance, efficiency, or economic sustainability of said product of human action. The development of these two complex tools has been carried out mainly in a theoretical framework, with significant difficulties for its comparison by the diversity of methodologies [16] and scopes in their application [17]. This is due to significant limitations that include the difficulty of understanding the used indicators, which can often be contradicted due to their independence, and the inexistence of a common unit of measure [18]. Additionally, oversimplification to economic unit in LCC [19] might lead to biases, like being able to bear with the costs allows compensation for the loss of environmental quality of the projects [20]. However, while this matter is still a problem in decision-making processes, new studies claim the relevance of economic compensation after environmental quality has already been achieved [21]. Other related tools are also employed, such as cost-benefit assessment (CBA), which seeks to link costs with both tangible (monetary) and intangible benefits [22], although terminological confusion regarding the methodologies and their scopes is frequent. This type of assessment focuses on the qualitative aspects of decision-making while maintaining consideration of economic factors, making it a fundamental tool for public investment [23]. A similar objective has driven the emergence of other indicators aimed at integrating economic and environmental dimensions, such as life-cycle costing and assessment (LCC+A) developed through the CILECCTA project [24], or life-cycle sustainability assessment (LCSA), both of them with challenges around functional units, applicability, or comprehensive coverage of social and environmental impacts [25]. The latter-mentioned LCSA surges in an effort to integrate the three pillars of true sustainable development under a unified European methodology by UNEP [26], combining LCC, LCA, and Social-LCA. This framework has inspired the European standard EN 15643 and shares similarities with the Whole Life Costing (WLC) indicator defined in ISO 15686-5:2017 [19] and the CBA defined by EU Guidelines [23]. It should be noted that this integrated perspective is necessary because traditional LCC methodologies have been unable to incorporate non-quantifiable elements such as intangible values and externalities. In fact, judgments regarding return on investment that fail to account for external and intangible costs often overlook the economic implications that developers' decisions may have on social and environmental impacts as well as on future profitability.