The traditional architectural design of care institutions is characterised by limited privacy, autonomy, user involvement, and rigidity in scheduling. In contrast, the Person-Centred Care (PCC) model presents an alternative approach to care provision, emphasising the active participation of the care recipient, involvement of the family, flexible scheduling, as well as a close relationship between users and caregivers. This approach requires reorganising facilities into smaller, more compact, self-contained units, known as living units. In Spain, the public administration responsible for social and health care centres (Imserso) has initiated the process of adapting its buildings to enhance social integration and implement the PCC model at a national level. The aim of this study is to outline and analyse the participatory process involved in evaluating the architectural design for the transformation of two such buildings. The research design is a multicentred descriptive case study with data collected through group workshops. The results describe the findings of four workshops conducted with care providers and care recipients of both buildings. Incorporating a co-design process with building users should be a fundamental aspect throughout all project phases, as deinstitutionalisation involves empowering individuals to participate and be active agents in their environments.