It is estimated that 80% of the buildings that will exist in 2050 have already been constructed. However, many of these buildings perform poorly in terms of energy efficiency and fail to comply with net-positive solutions. Natural soil is a low-embodied energy, recyclable, and healthy material that has been used for millennia in our buildings, following vernacular traditions and sustainable practices. When enhanced to be ecologically active, soil can support plant growth, offering a path to retrofitting buildings that enhance thermal insulation, expand green urban surfaces, improve air quality, and elevate both aesthetics and occupant well-being. Soils are considered ecologically active if they can provide the necessary humidity level and nutrition conditions for plant germination and long-term viability. This paper presents the rationale and the objectives of the Regenerative Retrofitting Via Ecologically Active Soil Structures (Reeco-Soil) project, which aims to establish a comprehensive understanding of the state-of-the-art and regenerative potential of retrofitting built environment assets using ecologically active soil structures. The study employs a methodology based on PRISMA guidelines. Preliminary results are presented according to keywords clusters and in terms of year publication distribution. Approximately 70% published within the last decade, indicating a strong and current evidence base. Ultimately, this project aims to generate a pathway to enable a flourishing relationship between humans and the living world by introducing a regenerative and innovative approach to building retrofitting.