1. Of the judgment of the first instance court, the part against the Plaintiff (Counterclaim Defendant) corresponding to the money that orders additional payment below.

The main lawsuit and counterclaim are also examined.

1. Basic facts

A. On April 6, 2016, the Plaintiff concluded a construction contract (hereinafter “instant construction contract”) with the content that the construction work for the instant construction work (hereinafter “instant construction work”) was subcontracted to the Defendant with ten household units with a size of 10,00,000 from the 4th floor above Ulsan-gun, Ulsan-gun, Ulsan-gun (hereinafter “instant building”).

B. On September 19, 2016, the Plaintiff and the Defendant agreed to perform additional construction related to the instant construction works, such as removal of reinforced concrete walls for multi-use rooms, and to pay the Plaintiff KRW 34,500,000 to the Defendant for additional construction costs (hereinafter “instant additional construction agreement”).

C. After that, on September 26, 2016, the Defendant completed the instant construction, and prepared a letter of intent to pay liquidated damages if it fails to do so, and then delivered it to the Plaintiff.

On the other hand, the Plaintiff paid a total of KRW 595,00,000 to the Defendant, including the additional construction cost as stipulated in the instant Additional Construction Contract.

E. On January 17, 2017, the Plaintiff underwent a completion inspection on the instant building.

[Ground of recognition] Facts without dispute, Gap evidence 1, 2, Eul evidence 1, 4, 16, the purport of the whole pleadings

2. Determination on the main claim

A. For the following reasons, the Defendant is obligated to pay to the Plaintiff KRW 123,374,080 (i.e., the construction cost paid in excess of KRW 5,500,000 for the non-construction and erroneous construction cost of KRW 61,774,080 for delay compensation of KRW 56,100 for delay), and damages for delay.

1) The instant construction cost was KRW 550,000,000, including value added tax, and the additional construction cost under the instant additional construction agreement was KRW 34,50,000,00, including value added tax. As such, the instant construction cost was KRW 584,50,000 in total, and the Plaintiff paid KRW 595,00,000 to the Defendant as the instant construction cost, and KRW 10,50,000 (=5,000,000 - KRW 584,50,000),00 in total.