BackgroundNew hospital design includes more single room accommodation but there is scant and ambiguous evidence relating to the impact on patient safety and staff and patient experiences.ObjectivesTo explore the impact of the move to a newly built acute hospital with all single rooms on care delivery, working practices, staff and patient experience, safety outcomes and costs.Design(1) Mixed-methods study to inform a pre-/post-‘move’ comparison within a single hospital, (2) quasi-experimental study in two control hospitals and (3) analysis of capital and operational costs associated with single rooms.SettingFour nested case study wards [postnatal, acute admissions unit (AAU), general surgery and older people’s] within a new hospital with all single rooms. Matched wards in two control hospitals formed the comparator group.Data sourcesTwenty-one stakeholder interviews; 250 hours of observation, 24 staff interviews, 32 patient interviews, staff survey (n = 55) and staff pedometer data (n = 56) in the four case study wards; routinely collected data at ward level in the control hospitals (e.g. infection rates) and costs associated with hospital design (e.g. cleaning and staffing) in the new hospital.Results(1) There was no significant change to the proportion of time spent by nursing staff on different activities. Staff perceived improvements (patient comfort and confidentiality), but thought the new accommodation worse for visibility and surveillance, teamwork, monitoring, safeguarding and remaining close to patients. Giving sufficient time and attention to each patient, locating other staff and discussing care with colleagues proved difficult. Two-thirds of patients expressed a clear preference for single rooms, with the benefits of comfort and control outweighing any disadvantages. Some patients experienced care as task-driven and functional, and interaction with other patients was absent, leading to a sense of isolation. Staff walking distances increased significantly after the move. (2) A temporary increase in falls and medication errors within the AAU was likely to be associated with the need to adjust work patterns rather than associated with single rooms, although staff perceived the loss of panoptic surveillance as the key to increases in falls. Because of the fall in infection rates nationally and the low incidence at our study site and comparator hospitals, it is difficult to conclude from our data that it is the ‘single room’ factor that prevents infection. (3) Building an all single room hospital can cost 5% more but the difference is marginal over time. Housekeeping and cleaning costs are higher.ConclusionsThe nature of tasks undertaken by nurses did not change, but staff needed to adapt their working practices significantly and felt ill prepared for the new ways of working, with potentially significant implications for the nature of teamwork in the longer term. Staff preference remained for a mix of single rooms and bays. Patients preferred single rooms. There was no strong evidence that single rooms had any impact on patient safety but housekeeping and cleaning costs are higher. In terms of future work, patient experience and preferences in hospitals with different proportions of single rooms/designs need to be explored with a larger patient sample. The long-term impact of single room working on the nature of teamwork and informal learning and on clinical/care outcomes should also be explored.FundingThe National Institute for Health Research Health Services and Delivery Research programme.