Of the judgment of the court of first instance, the part against the plaintiff in relation to the defendant B, which orders payment.

1. Basic facts

A. Defendant C Co., Ltd (hereinafter “Defendant C”) is a corporation that runs a construction business.

B. As to the construction of the main complex building to be constructed in Ulsan-gu, Ulsan-gu (hereinafter “instant building”), the Defendant Company contracted the construction of the following construction works: (a) around April 2017, Defendant B made an oral subcontract to the Plaintiff for the waterproof Construction Work during the instant construction works (hereinafter “instant waterproof Construction”).

C. From May 25, 2017 to November 26, 2017, the Plaintiff performed cement liquids and cement mortar construction work from the third floor to the tenth floor above the above building’s ground. D.

Defendant B paid to the Plaintiff KRW 5 million on September 30, 2017, and KRW 15 million on December 10, 2017, respectively, to the Plaintiff.

[Grounds for Recognition] Facts without dispute, Gap evidence 2, 3, 6, Eul evidence 1 and 3 (including each number; hereinafter the same shall apply), the purport of the whole pleadings (including the opinion of the professional examiner E)

2. The parties' assertion

A. The Plaintiff’s assertion 1) agreed on the cost of cement waterproof construction with Defendant B at KRW 10,00 per square meter in floor area. The cost of liquid waterproof construction based on the floor area from the third floor of the instant building to the tenth floor of the ground that the Plaintiff performed the said construction work is KRW 34,840,000. (2) The cost of waterproof waterproof construction with Defendant B was to be paid separately from the said cost. The cost of waterproof construction is KRW 5,000 per square meter. The Plaintiff’s construction cost of the part calculated accordingly is KRW 10,242,400.

3) The Defendant Company also has the duty to pay the construction cost for the part of the Plaintiff’s construction work as the ordering person. The Defendants jointly and severally have the obligation to pay the Plaintiff the total amount of the unpaid construction cost of KRW 25,082,40 (i.e., liquid waterproof construction work of KRW 34,840,000) - Defendant B’s payment of KRW 10,242,400 for waterproof construction work of KRW 10,240,000, and damages for delay, even if the said amount is not recognized.