1. The plaintiff's appeal is dismissed.

2. The costs of appeal shall be borne by the Plaintiff.

The purport of the claim and appeal is the purport of the appeal.

1. The parties' assertion

A. The Plaintiff’s assertion (1) The Defendant: (a) subcontracted the H construction work of C Co., Ltd. that was contracted by C to C (the “E”) to D; (b) but, as D was engaged in the said construction work, it was obligated to pay the said additional construction cost (hereinafter “instant additional construction cost”) to the Plaintiff who received the claim for the said additional construction cost from D.

(2) Since D completes the subcontracted I Corporation and is not paid the price of KRW 4,622,432 (including value-added tax) by the Defendant, the Defendant is obligated to pay the said construction cost to the Plaintiff that received the claim for the said construction cost from D (hereinafter “instant unpaid construction cost”).

B. The defendant's assertion (1) D does not have any additional construction work at the above H construction site.

(2) Rather, D’s defect defect repair works worth KRW 11,941,365 due to the occurrence of defect in HG subcontracted construction works. If the defect repair construction cost is offset against the unpaid construction cost claim, the Defendant’s claim for construction payment is extinguished in entirety by offset against the Plaintiff.

2. Determination

A. (1) The evidence alone presented by the Plaintiff is insufficient to recognize that D had an additional construction work at the H construction site.

(2) Rather, according to the following facts, Gap evidence Nos. 1 and Eul evidence Nos. 1 through 4, F and D witness of the first instance trial, the inquiry results by the head of Hongsung Tax Office, and the purport of the whole pleadings, the following facts can be acknowledged.

(A) On July 2014, D around July 2014, the Corporation was not an additional construction but a defect repair project related to the existing construction, which was conducted at the request of C, a main contractor, and there was no fact that the Defendant ordered D additional construction.

(B) The first instance court held D also.