1. The Defendant’s KRW 22,286,163 as well as the Plaintiff’s KRW 6% per annum from June 22, 2018 to February 6, 2020, and from February 7, 2020.

1. Basic facts

A. The Plaintiff is a personal entrepreneur who runs a construction business, such as heating construction business, with the trade name of C.

B. As of April 29, 2016, the Defendant awarded a contract to the Plaintiff with the construction cost of KRW 100,000,000 for the construction work of constructing a new building on the ground of Gangwon-gun D, Gangwon-gun.

(hereinafter “instant contract”). (c)

The Plaintiff performed a contracted construction under the instant contract, and the Plaintiff’s detached housing building built by the Plaintiff (hereinafter “instant building”) obtained approval for use on December 23, 2016, and the Defendant completed registration of preservation of ownership on December 27, 2016.

The current status of the instant building at the time of approval for use is 103.78 square meters of the block structure of the first floor and 23 square meters of the second floor.

[Ground of recognition] Facts without dispute, Gap evidence 1, 2, 3, Eul evidence 1, the purport of the whole pleadings

2. The plaintiff's assertion and judgment

A. A summary of the Plaintiff’s assertion is as follows.

① Since the Defendant paid only KRW 80,000,000 among the construction cost to be paid according to the instant contract even if the Plaintiff completed the instant building, and did not pay the remainder of KRW 20,000,000,000, the Defendant is obligated to pay the Plaintiff the unpaid construction cost.

② The construction cost stipulated in the instant contract was determined on the basis of the floor area of 36 square meters, and the Defendant demanded that the main walls, etc. be accumulated behind the passage of the construction work, while paying the additional cost, unlike the original design drawing, and the floor area of the second evaluation also increased, the Defendant is required to pay the additional construction cost following the increase in the floor area. The construction cost related to the increase in the floor area is equivalent to KRW 3,528,67. At the Defendant’s request, the construction cost related to the increase in the floor area of the multi-use room is equivalent to KRW 3,528,67, and the construction cost of the multi-use room, water pipe, waste water pipeline, etc. was additionally added, and