Formed in the mid-nineteenth century, the building societies grew rapidly from their humble beginnings as localized ‘self-help’ institutions to become the dominant players in the house mortgage market by the interwar period. Throughout their early history, the societies presented themselves as champions of home ownership among the working classes, but historians of housing have generally disputed the role that building societies played, or could have played, in extending home ownership before the First World War. The case study presented in this article shows that it was possible for a building society to lend to working-class borrowers, and that home ownership before the First World War was not beyond the grasp of such people. While it was undoubtedly an exception within the movement, the Co-operative Permanent Building Society showed a genuine commitment to working-class owner-occupation, providing the majority of its loans to both skilled and unskilled workers on easy repayment terms. How it was able to overcome the adverse selection and moral hazard risks involved in lending to such groups of people is the focus of this article.