A. On April 27, 2015, the Plaintiff entered into a contract with the Defendant and the Defendant, setting the construction cost of KRW 40 million and the construction period from April 28, 2015 to June 30, 2015 with respect to “the 40 million construction cost for the 2nd floor remodeling construction among the 3rd floor in Gwangjin-gu Seoul Special Metropolitan City, which is owned by the Defendant,” and the same year.

5. From among the above buildings, the construction cost of KRW 36 million was determined as the construction cost and the construction period from May 16, 2015 to June 30, 2015, with respect to the removal, waterproofing, and fenceing installation works for the fourth floor floor remodeling construction and rooftop sections.

The above two works are referred to as "the construction of this case".

B. The Plaintiff completed the instant construction around June 30, 2015, and the Defendant from April 28, 2015 to the same year.

7. By August, 700, the Plaintiff paid KRW 73,000,000 to the construction cost of this case.

[Ground of recognition] Facts without dispute, Gap evidence 6, 7 evidence, Eul evidence 1-1 and 2, and the purport of the whole pleadings.

2. Determination

A. (1) According to the facts of the determination as to the claim for construction cost of this case, the Defendant is obligated to pay the Plaintiff the amount payable to the Plaintiff for the construction cost of KRW 3,000,000 (= KRW 40,000,000 - KRW 73,000,000) and damages for delay.

(2) (A) The Plaintiff’s assertion on the claim for the additional construction cost was under construction work until July 29, 2015, as indicated in the “written confirmation of the details of the additional construction work,” at the Defendant’s request from the day before July 29, 2015. However, the Defendant installed the additional construction work amounting to KRW 19,950,00 [i] ① (i) rooftop rail and rooftop entrance door around May 26, 2015, KRW 3,950,00, ② (ii) four-story rail lines around May 29, 2015 (the fourth floor entry door, the fourth floor beer, the fourth floor beer window, the second and fourth floor window beer, the second and fourth floor window beer 3,00,000, ③ the installation of the outer entrance entrance entrance at the external parking lot around May 29, 2015, and around KRW 3,000,00,000.