The defendant's KRW 26.4 million to the plaintiff and its 6% per annum from October 5, 2019 to June 18, 2020.

1. Basic facts

A. The Plaintiff is a company whose purpose is the interior metal construction business, etc., and the Defendant is a company whose purpose is the interior metal construction business, etc.

B. On March 15, 2018, the Defendant entered into a subcontract (hereinafter “instant contract”) with the Plaintiff on the construction cost of KRW 45 million with respect to the metal work during the said construction work (hereinafter “instant construction work”) and the construction period from March 16, 2018 to May 22, 2018.

C. On May 22, 2018, the Plaintiff completed the instant construction work, and the additional construction works not included in the instant contract were also implemented.

By June 15, 2018, the Defendant paid the Plaintiff the construction cost of KRW 45 million (excluding surtax) as stipulated in the instant contract, and paid the additional construction cost of KRW 60 million (excluding surtax) on December 28, 2018 and January 21, 2019, respectively.

[Ground of recognition] The fact that there is no dispute, entry of Gap's 1 through 3, purport of whole pleading

2. The assertion and judgment

A. The summary of the parties' assertion (1) The plaintiff defendant is obligated to pay 32 million won as additional construction cost (excluding additional tax) and damages for delay, as the remaining 26.4 million won [=2.4 million won [=32 million won - 2.4 million won additional tax)] and damages for delay.

(2) The defendant did not have to demand additional construction works or pay the additional construction cost to the plaintiff.

The Plaintiff, after receiving the full payment of the construction cost under the instant contract, concluded that the additional construction cost would be changed.

However, the fact that the Plaintiff had partially verified the additional construction works, and only paid 8 million won (excluding surtax) in return for it.

The defendant is no longer liable to pay the additional construction cost.

B. We examine the judgment, and arguments set forth in Gap evidence Nos. 4 to 6.