Life Cycle Assessment should not be treated as an end-of-project report: it is a tool to design better

In recent years, the term Life Cycle Assessment —LCA, or Análisis de Ciclo de Vida (ACV) in Spanish— has gained visibility in the building sector, driven by European regulations, environmental certifications, and decarbonisation commitments. Yet a widespread misconception persists: many professionals still regard LCA as a final deliverable, a document required merely to comply with a standard. In reality, its greatest value lies in conceiving and applying it as a design tool —one that helps identify opportunities for improvement and implement them while there is still time to do so.

LCA, as defined by ISO 14040:2006 and developed in ISO 14044:2006, is a standardised methodology used to quantify the environmental impacts associated with a product, process, or building —from raw material extraction to end of life. In the construction sector, this approach is articulated through the European standard EN 15978:2011, which sets out the calculation method for assessing the environmental performance of buildings and organises the life cycle into the following stages: product stage (A1–A3), construction process (A4–A5), use and maintenance (B1–B7), and end of life (C1–C4), together with potential benefits beyond the system boundaries, defined as stage D.

The regulatory framework is complemented by EN 15804:2012+A2:2019, which governs Environmental Product Declarations (EPDs) as the primary data source for construction materials; EN 15643-1:2021, which defines the framework for assessing the overall sustainability of construction works; and EN 15942:2022, which harmonises the communication of LCA data between manufacturers, designers, and verifiers. In addition, the European Commission has consolidated this approach through the Level(s) framework (European Framework for Sustainable Buildings, 2021), which unifies criteria and methodology for generating and comparing environmental, social, and circularity indicators, and through Regulation (EU) 2020/852 —the EU Taxonomy for Sustainable Finance— which sets out the parameters by which an activity can be considered sustainable and requires verifiable evidence, including LCA results, to demonstrate alignment with the EU’s climate objectives.

In this context, LCA should not be understood as a final audit but as a dynamic process of learning and continuous improvement, a path that accompanies the entire design process and extends into the construction phase. Its real value emerges when applied from the earliest design stages —when decisions on materials, construction systems or energy solutions can still be adjusted and substantially influence the building’s overall impact. Used in this way, LCA ceases to be a mere accounting exercise and becomes a strategic project tool, capable of guiding architectural and engineering decisions towards scenarios with lower environmental footprints and greater coherence with decarbonisation goals. Crucially, this must come with the active involvement of the developer, who needs to understand and accept that some decisions may imply a small increase in cost, but also a tangible increase in long-term value.

The problem is that, in practice, LCA is still too often applied as a post-hoc audit, when the project is already defined or even built. In such cases, the tool loses its transformative potential: the impacts have already occurred, and the LCA becomes a mirror reflecting what could have been avoided. What matters is not the report that is delivered, but the knowledge process it generates.

Integrating LCA from the outset makes it possible to compare design alternatives, quantify how each decision modifies both impacts and costs, and act as an empirical justification for the choices made in materials and systems. It is, in essence, a common language between designers, developers, operators, and auditors. In projects where LCA has been implemented early —following schemes such as BREEAM, DGNB, or Level(s)— reductions of up to 40% in carbon emissions across the building’s full life cycle have been achieved. Forty per cent fewer emissions than the initial design concept: a figure that should be repeated as many times as necessary until we truly grasp its significance and transformative capacity.

Its usefulness extends into the construction phase, where changes and substitutions of materials frequently arise. In these cases, applying LCA dynamically allows teams to evaluate the impact of each modification and maintain alignment with the project’s initial environmental goals. It becomes a compass, a logbook, as essential to environmental management as the schedule is to time or the budget is to cost control.

Moreover, the data generated by a well-structured LCA can be directly integrated into environmental reporting systems required under the EU Taxonomy, ESG criteria, or the Level(s) indicators. LCA provides a technical, objective, and verifiable foundation for reporting a project’s performance in terms of climate mitigation, resource efficiency, and circular economy.

The UK Green Building Council, in its Whole Life Carbon Roadmap (2021), reminds us that more than 80% of a building’s total emissions are determined during the design phase. This means that the potential for improvement diminishes as the project advances. Applying LCA from the beginning is therefore not a matter of compliance but of project intelligence: the most effective and economical way to reduce impacts before they occur, anticipate decisions, and document real benefits.

For this reason, the sector must evolve from a documentary mindset towards an operational and proactive vision of LCA. It is not enough to deliver a report at the end; it is essential to work with the tool throughout the process. LCA is not a product to be handed over, but a process to be accompanied. Its role is not to close a file, but to open a technical conversation about how to build better.

The environmental maturity of the sector will depend, to a great extent, on whether developers, technicians, and public administrations grasp this distinction. If we continue to treat LCA as a formality, it will remain a useful but sterile document. If, instead, we embrace it as a project tool, it will become a genuine instrument of transformation —one capable of steering every decision towards a more conscious, measurable, and responsible architecture.

Because, in the end, LCA is not the photograph of impact: it is the camera through which we decide where to focus.

Ricard Santamaría
Managing Partner, HAUS Healthy Buildings