The article aims to illuminate the hidden path by which a symbolic dimension in a traditional society is transferred to the modern world. The modernization process in Seoul during the second half of the twentieth century was one of the most intense and radical. The traditional courtyard house, which had been the single form of dwelling in the city for centuries, was replaced by modern houses within a few decades. Apartment housing became the most dominant housing type, and this new spatial setting reshaped domestic lifestyles. At the surface level, there seems to be no connection between the old and new housing culture. A series of analyses reveals, however, that there exists a hidden dimension of “level distinction,” i.e. a conceptual differentiation between high- and low-level floors that has not only survived the radical change, but also guided the direction of contemporary housing development.