This paper reports on an in-depth qualitative study of the diffusion of digital innovation in a large UK engineering firm. Previous research in the diffusion of innovations in construction emphasises either projects or the firm with little attention to the interface between the firm and its projects, and the effect of this interface in diffusion processes. This research however employs a contextualist process approach which accounts for more than the individual choice, and considers non-linearity and iteration within the chronology of a diffusion process. The findings of this research provide a case for learning and capabilities development for BIM across the firm through strategic technology group which the firm mobilised to provide innovation championship and digital leadership. It also captures important tensions and challenges at the interface between the firm and its projects, which are largely related to the need for standardised processes across the firm to achieve repeatable solutions, and at the same time being able to meet the unique requirements of specific markets and projects. The implications of these findings in practice and in research in the diffusion of innovations in construction are discussed.