Methodological framework for impact evaluation of Building-Integrated Greenery (BIG-impact).

Building-Integrated Greenery systems, i.e., green roofs, walls, and facades, are Nature-based Solutions that make possible the renaturing of cities when there is no room for traditional greenery solutions. These green systems provide several ecosystem services at both the building and city level, such as urban heat island effect mitigation and noise reduction, support for biodiversity, runoff control, thermal and acoustic insulation, etc. However, once implemented in real cases, their impact is almost never evaluated. This fact limits the possibility of carrying out cost-benefit analyses that contribute to justifying their long-term maintenance, thus putting at risk their long-term sustainability and consequently the provision of benefits. Unlike existing approaches, the method presented here offers a comprehensive and practical tool that addresses the gap in BIG systems' impact evaluation, facilitating informed decision-making and promoting the long-term sustainability of BIG systems.•In its design, the current references at European and global level for building-integrated systems impact assessment has been considered.•It is easily replicable in any real project and enables the collaboration of involved stakeholders.•The method is unprecedented and allows a holistic assessment of the impact of BIG in real cases, in terms of ecosystem services provided.