Design quality work has sought to identify the impact of building design on users during the last 25 years. However, it has rarely considered the role that social context plays in this relationship, an issue that dovetails with the emerging concept of "social value". To drive learning in design, the social value of buildings requires measurement and dissemination, yet existing post-occupancy methodologies have focused on technical building performance rather than user experience. A shift in evaluative focus is needed. The social value of buildings is conceptualised as the mutual interaction between physical building design, active building users and the dynamic social relations that exist within the community of building users. This research has investigated the effective measurement of the social value of buildings and its potential influence on learning in design and commissioning processes, through the critical application of a social impact methodology called Social Return on Investment (SROI). Three case buildings were selected from the nonclinical healthcare sector with differing levels of user-centred design to trial SROI and develop a framework for its application to the built environment. SROI is designed to quantify complex social outcomes, identified through qualitative stakeholder engagement, and generate a transferable metric in the form of a monetised return-on-investment ratio. A methodological account is given of the challenges faced when applying it to the case buildings and the modifications required as a result, representing a unique information source about applied social value research in buildings. However, the effectiveness of SROI at measuring the social value of buildings is questioned due to the process of simplification required to turn qualitative user narratives into monetised data. Its potential utility as a decision-making tool in the built environment is investigated through engagement with design and commissioning professionals. The findings suggest that SROI has limited utility in design-related decisions, but considerable potential as a high level investment tool to inform funding and commissioning decisions. Due to the accessibility of its methodology and transferability of its results, SROI is well-placed as a tool for end user clients, commissioners and investors, as much as design experts. SROI represents a development in lay (e)valuation practices in the built environment, with broader implications for user-centred learning in the context of the growing wellbeing agenda.