Most vernacular and traditional buildings are considered as 'timeless' meaning that their forms and styles are accepted as 'objects' that do not change over time. This leads to rigid definitions of domestic architecture by assigning definite cultural meanings to physical forms. While vernacular domestic spaces naturally represent the culture and society that they are constructed in, where these are interpreted in the light of fixed notions of 'culture' and 'tradition', the possibility that 'vernacular' does not necessarily mean 'timeless' or 'unchanging' is left unexplored. This paper re-examines the boundaries of nation-specific 'vernaculars' through a comparative cross-cultural analysis of traditional housing. It interrogates the use of notions such as 'culture' and 'tradition' in vernacular housing typologies in Turkey, Japan and Britain in order to provide a better understanding of 'the vernacular' as a dynamic concept in domestic architecture. It proposes a comparative interpretative framework for studying the vernacular by considering how the relationship between the social and spatial patterns is shaped under diverse regional and historical conditions. This approach raises questions for conventional definitions of the 'vernacular' by analysing similarities as well as differences between the different traditions. The research applies space syntax methodology to 30 different vernacular housing examples built between 17th and 19th centuries in different regions of Turkey, Japan and Britain, each held to represent the 'national' values and traditions of their particular culture. The results of the analysis show how the traditional typological approach to housing forms remains insufficient to fully understand vernacular architecture, since it tends to elide differences in social mores and the use of domestic space into a single 'vernacular' tradition. Overall, this study shows how the conventional classifications of vernacular architecture depending on cultural and national traditions do not go much beyond creating normative statements that are mainly taken for granted. By contrast, the research presented here proposes the 'vernacular' as a fluid, rather than a fixed description of national traditions of domestic architecture