A. On April 5, 2017, the lower court ordered the Plaintiff to extend and remodel (construction and remodelling (construction, machinery) facilities in agricultural communities, and the Plaintiff concluded a subcontract contract for the construction of machinery and equipment (hereinafter “instant subcontract contract”) during the instant construction work with the Defendant (hereinafter “instant construction work”).

B. On April 5, 2017, the Plaintiff and the Defendant drafted a written subcontract for the instant construction project (hereinafter “instant first subcontract agreement”) with the construction period stipulated as “the commencement date of construction works, April 10, 2017, May 31, 2017,” “75,000,000 won” and “10% of the defect liability rate” (hereinafter “instant first subcontract agreement”).

C. On May 2017, the Defendant’s execution of the instant construction project, such as the request for design change and the refusal thereof, and the result of the appraisal of the additional construction cost as to the Defendant’s execution of the instant construction project and the result of the appraisal of the said additional construction cost, as stated in the attached Form “the result of appraisal of the amount of additional construction work”, differently from the contents of the instant subcontract at the request of the Innju City and the Plaintiff.

(2) On May 21, 2017, the Defendant sent to the Plaintiff a letter of request for design change, which added the construction cost of KRW 10,597,00 to the Plaintiff in accordance with the instant alteration work, and subsequently, sent a letter of request for design change, which requires the Plaintiff to increase the construction cost on May 22, 2017, and the Defendant requested the Plaintiff to change the construction cost in response to the instant alteration work.

Accordingly, on May 23, 2017, the plaintiff also submitted a written request for design change delivered by the defendant at the time of Innju.