1. The plaintiff (Counterclaim defendant)'s main claim is dismissed.

2. The Plaintiff (Counterclaim Defendant) is KRW 10,488,191, to the Defendant (Counterclaim Plaintiff).

1. Basic facts

A. On November 20, 2015, the Defendant: (a) determined the contract amount of KRW 125,000,000 (original construction cost of KRW 12,000,000); and (b) determined the rate of liquidated damages for delay as 1/1000 of the daily contract amount on May 30, 2016; and (c) concluded a contract for the instant construction of the C-ground Housing (hereinafter “instant construction”) with the Plaintiff (hereinafter “instant contract”).

B. On August 9, 2016, the Plaintiff and the Defendant agreed on the additional construction and interim settlement related to the instant construction (hereinafter “instant agreement”) with the purport that “any defect and finish related to the installation of a window are constructed by the building owner; the alteration of the ceiling height was executed at the request of the building owner; the additional construction cost of KRW 3,700,000 was incurred; the construction cost of KRW 7,000,000 was increased in connection with the construction of the instant construction.”

C. On December 22, 2015, the Defendant paid to the Plaintiff KRW 95,00,000 in total, including KRW 37,500,000,000 on the construction cost, and KRW 10,000 on January 27, 2016, and KRW 37,50,000 on March 18, 2016, and KRW 10,000 on May 23, 2016.

On February 16, 2017, with respect to the housing newly built by the instant construction project (hereinafter “instant housing”), the approval for use was granted.

[Ground of recognition] Facts without dispute, Gap 1, 3 evidence, Eul 1 and 4 evidence, the purport of the whole pleadings

2. Judgment on the plaintiff's main claim

A. The plaintiff and the defendant have been found to have agreed on the cause of the principal claim in this case that the defendant directly paid the price related to the creative construction among the construction works of this case and that the defendant recognized the additional construction cost of KRW 10,700,000 due to the alteration of ceiling height and the structural construction works. The defendant is obligated to pay the plaintiff the additional construction cost of KRW 28,700,000 (= the aforementioned additional construction cost of KRW 125,700,000 for the first construction cost of KRW 125,70,000 for the first construction cost of KRW 12,00,000 for the creative construction cost of KRW 12,00 for the construction cost of this case - the construction cost of KRW 95,00,000 for

B. Of the instant agreement on the Defendant’s assertion, the Defendant regarding the structural construction cost among the instant agreement.