Purpose This paper aims to identify and discuss how process and people factors influence the successful implementation of organisational interface management in offsite bathroom construction. Design/methodology/approach A literature review identified 16 process and people factors. A mixed method approach was used to analyse data from eight offsite bathroom case study projects. A ranking approach determined the main process and people factors, consequently analysed using (Minitab) Frequency analysis, the Wilcoxon Signed Rank test and thematic analysis to establish the contributing sub-factors and their inter-relationships, to each other and to the literature. These factors and sub-factors formed the final conceptual model, bringing together interface management and offsite bathroom construction. Findings The nine factors instrumental to the conceptual model include six process factors: procurement, design management, supply chain management, health and safety, tolerance and quality and three people factors: communication, client/design team and project manager, reflecting the construction industry focus on hard processes over soft. The role of the project manager and communication, however, are the main factors which contribute to overall project success. Direct management of the offsite works by the contractor’s project manager is also highly significant. Research limitations/implications Limitations include the (UK) geographical focus of the research and the focus on bathroom pods in buildings. Social implications The research recognises three people (social) factors: communication, client/design team and project manager, with the first and third being the main factors which contribute to overall project success. Originality/value Originality stems from the focus on organisational interface management and how this relates to offsite bathroom construction (a practice gaining considerable momentum in industry) and the resultant model. Being grounded on more than one body of academic literature as well as 8 case studies and 82 industry interviews, there is value to both researchers and construction industry practitioners alike.