In traditional architecture of East Asia, a distinct feature is the clustering of multiple buildings to form a single-unit. Therefore, the expansion of a single-unit building has not been given as much consideration as in Western architecture. This study aims to examine the planar and sectional scales in the Kan composition of traditional Korean architecture and to identify the limitations of scale expansion. Although previous studies have focused on the characteristics of the plan and section, this study is the first to conduct a comprehensive survey of all nationally designated cultural properties and derive statistical significance. The typical plan configuration consists of three bays for both the front and side, which emphasizes the facade. However, a plan with a side of five bays is relatively uncommon, and there are no examples of buildings in Korea exceeding five bays. This can be attributed to the structural characteristics of East Asian wooden architecture, where expansion to the side is difficult and the desire for depth and height is not prominent. In contrast, China and Japan have buildings with a side length of six and seven bays, respectively, allowing for a more expandable limit of scale.