A. D Co., Ltd. (hereinafter “D”) is the owner of the E Co., Ltd.’s factory construction work (hereinafter “this case’s factory construction work”). On April 4, 2016, among the aforementioned factory construction work, D Co., Ltd. awarded a contract for manufacturing and installing environmental (water quality) preventive facilities, such as the attached drawing, to Defendant C (hereinafter “Defendant C”), and Defendant C awarded a subcontract for manufacturing and installing the above factory construction work at the surface processing PP of the parts inside and outside concrete tanks among each tank in the attached drawing. D Co., Ltd awarded a subcontract to F Co., Ltd. operated by Defendant B with the construction cost of KRW 10 million (value-added tax separately).

B. On May 2016, the Plaintiff was sub-subcontracted by Defendant B with the construction cost of KRW 45 million during the process of construction of mining (hereinafter “instant construction”).

(hereinafter “instant contract”). C.

Defendant B paid the Plaintiff the down payment of KRW 13.5 million on June 2016, and the Plaintiff continued the instant construction work from July 20, 2016.

한편, 콘크리트 구조물 설치작업이 일응 마무리된 2016. 8. 중순경 기제작된 콘크리트 구조물의 상하부 폭이 균일하지 않거나 중앙 부위의 휨 현상, 라이닝쉬트와 콘크리트 벽면의 부착상태 불량 등의 문제가 발생하였다.

E. On August 2016, H, the production general manager of D, and the person in charge of Defendant B, and Defendant I (hereinafter “I”), the former representative director of the Plaintiff, K, the above J acknowledged that the pre-produced concrete problem was due to the defect in the part of the civil works undertaken in I, and there was a consultation for reconstruction after removing the concrete structure installed in I.

F. Meanwhile, in order to install a “tank”, which is an environmental pollution prevention facility, a concrete structure should be installed both at first, and at this time, the Plaintiff is the primary concrete on the surface of the Furgy.