The built environment influences the well-being of older people in care homes. In order to design for enablement, physical activity, and social connectivity there are lessons to be learnt from current care home buildings. Uncovering this design information is key for the future improvement of environments for older people. To the field of architecture, this paper presents an analysis of ethnographic observations (utilizing an adapted form of the AEIOU heuristic) from five urban care homes in the UK. Findings provide insight into the qualities of the built environment that have impact on the activity and potential well-being of older residents. Five significant qualities of the built environment are identified:  Spatial Legibility, Spatial Interconnectedness, Spatial Traversability, Spatial Diversity, and Spatial Aesthetics.