Like apartment buildings in Korea, condominiums in the United States are not a physical style or type of building, but rather a mode of ownership. In addition to the physical elements of private and common areas, condominiums in the U.S. also have an owner's association as a human element. However, unlike Korea, the human factor is much stronger than the physical factor. This is because the U.S. condominium law focuses on collective management of property. On the other hand, the Korean Collective Buildings Act has emphasized the right of separate ownership of the exclusive use part from the time of its enactment, as it originated from the modification of the sharing theory of the civil law to adjust the sharing relationship between the exercise of ownership of each exclusive use part and the common part or land, and to promote the survival of each unit owner with respect to the sharing relationship. However, collective buildings in Korea are becoming larger and larger, and large apartment complexes with many facilities are becoming more popular, and the proportion of common areas to the total area is increasing. Therefore, even in the Collective Building Act, it is necessary to strengthen the human factor through the community of residents to manage the common areas and control the interests of users of the common areas, such as noise between floors.