The judgment below is reversed, and the case is remanded to the Seoul Southern District Court.

The grounds of appeal are examined (to the extent of supplement in case of supplemental appellate briefs not timely filed).

1. In order to establish sectional ownership for one building, there shall exist one building in objective physical and physical aspects, and separate sections of the building shall be in structural or practical independence, and physically partitioned parts of one building shall be the objects of sectional ownership;

Here, the act of partitioning is a kind of legal act intending to divide a specific part of a building into an object of separate ownership, and there is no special limitation on the time and method, but the intention of the disposal authority should be objectively indicated.

(See Supreme Court en banc Decision 2010Da71578 Decided January 17, 2013 (see, e.g., Supreme Court en banc Decision 2010Da71578, Jan. 17, 2013). In the case of a part of a general building that is used by the owners of an aggregate building, the determination of whether the establishment of sectional ownership

The underground floor of multi-household housing is often used by the owners of divided buildings. If the underground floor was illegally constructed without permission for construction while constructing one multi-household building, it is in line with the social concept and trade practice, insofar as the intention of classifying the disposal authority is not clearly indicated.

2. According to the reasoning of the lower judgment and the record, the following facts are revealed.

The multi-household housing in this case is a multi-family housing constructed on the 1st underground floor and the 5th above ground floor, and there are 8 households of a sectioned building on the 1st floor among the 4th floors, and on the remaining 4 floors.

The defendant's wife G newly built the above multi-household house as the owner of the building, and obtained approval for use on or around December 29, 2003, and January 2004.