This paper examines the formation of a cross-sector partnership in which a collaborative response addressed the issue of affordable housing and homelessness in Melbourne, Australia. Factors leading to the formation and evolution of the relationship reveal how social partnerships in the housing/construction industry can be formulated. Semi-structured interviews were held with representatives of the three sectors involved in an innovative social housing model, the Elizabeth Street Common Ground project. Supported with background documentation, interviews were coded and the results contrasted against theories pertaining to cross-sector collaboration.