Evolutionary Characteristics of Floor Plan Design in Public Rental Housing in Korean New Towns: Case Studies from 1990 to 2010

Since the 1980s, South Korea has continuously supplied public rental housing alongside the development of new towns. However, systematic studies examining the relationship between qualitative changes in floor plan design and the institutional factors influencing them remain limited. This study is based on the premise that floor plans in public rental housing are not merely the result of design improvements, but are structurally shaped by legal and institutional frameworks. It systematically analyzes changes in floor plan types and planning elements according to development periods and housing sizes. To achieve this, this study examines public rental housing supplied in Korean new towns from the 1990s to the 2010s, classifying floor plan types by period and housing size and analyzing their planning characteristics. The analysis focuses on the composition and arrangement of interior spaces, the size of each space, bay structure, and aspect ratio. A comparative analysis further examines the relationship between floor plan changes and relevant laws and institutional frameworks. The results show that floor plan configurations evolved in distinct phases in response to institutional changes and housing size differentiation. In the 1990s, standardized one-bay layouts with integrated living and sleeping spaces were predominant under strict regulatory conditions, including spatial dimension constraints. In the 2000s, following the legalization of balcony extensions, floor plans diversified into two-bay and three-bay configurations. In the 2010s, floor plan types became increasingly diversified and complex under the influence of district unit plans and detailed design guidelines issued by public agencies. In terms of housing size, smaller units (around 20 m2) maintained simplified one-room configurations, while medium-sized units (around 30–40 m2) exhibited a clear transition from integrated to functionally separated layouts, and larger units (around 50 m2) showed a significant increase in spatial diversity and variation in layout composition. These findings indicate that floor plan evolution is not a linear process of design improvement, but a structurally conditioned transformation shaped by regulatory frameworks, institutional changes, and path dependency. The persistence and gradual modification of earlier standardized layouts suggest that floor plan configurations are continuously reproduced and adapted within institutional constraints. By empirically identifying the structural relationship between institutional frameworks and floor plan design, this study reveals the mechanisms through which institutional conditions shape housing design. Furthermore, it contributes to an interdisciplinary understanding that integrates architecture, urban planning, and housing policy, and provides important implications for design guidelines and policy development aimed at improving the quality of public rental housing.