This study aims at understanding the changing public private relations in housing environments designed and produced after 80.s as a consequence of redefined context of 20th century life style and housing models. The study also aims to examine and display the transactions of the modernization processes in Turkey. Especially the mass housing settlements, in İzmir are chosen as study areas. The study evaluates the quantitative and qualitative properties of the settlement areas in which masss produced housing units are used repeatedly and monotonously.The .garden city. and .satellite city., which are accepted as the 20th century modern settlement models are surveyed, and their spatial transformations are analyzed. In this framework, the reflections of urban spatial transformation in Europe and Turkey are evaluated whitin the context of city of Izmir. Especially, the presence of semi-private areas, which hold the opportunity, and the spatial potentials of socialization such as gathering, collecting, intersecting, confronting, are surveyed within five different mass housing site examples in Izmir. From the .private space., which is the basic .housing unit. to . public space., levels of the spatial hierarcy, (which is the subject of social psychology), meant to be put forward. The transition spaces, which are semi- private and semi-public, are argued as to whether they constitute criteria in contemporary design applications. Such a concern is evaluated by comparative analysis. The study suggests to create a qualitative contribution for futher designs of quantitatively designed mass housing environments.Key words: modern settlement models, housing spatial transformation, housing pattern/hiyerarchy (public, semi-public, semi-private and public spaces), privacy concept in housing, spatial quality.