In this paper, design principles for a co-housing project focused at young adults (18-27 years old) wishing to live in the Tarwewijk in Rotterdam Zuid are being proposed. These principles are based on literary research, reference projects, fieldwork and workshops held for students familiar with the design location. Topics that are touched upon are affordability, co-housing principles and the living wishes of young adults wishing to live in Rotterdam Zuid. While the target group did not perfectly fit the proposed target group, results were interpreted as if they were. The most important findings through different methods of research, among others, include that different types of housing should be realised, the building should contain several shared facilities in rooms which have a flexible floorplan, the neighbourhood should be involved in shared spaces, housing units should be designed as small and with as little walls as possible and that bathrooms and bedrooms should always be private. These results were combined into a design brief specifically created for the Tarwewijk in Rotterdam Zuid, yet the basic principles can be implemented in other affordable co-housing projects as well.