A. The Plaintiff’s assertion ① Around February 23, 2018, the Plaintiff and the Defendant concluded a contract for C Child Care Center interior work amounting to KRW 47 million.

On August 2018, the Defendant completed construction and the Plaintiff paid the construction cost of KRW 47 million until October 2018.

However, from December 2018, the Defendant claimed for the payment of additional construction cost of KRW 34,060,000 to the Plaintiff.

The additional construction works asserted by the defendant are all included in the main construction works, and the plaintiff did not agree to pay a separate construction cost with the defendant in regard to additional construction or alteration works.

Therefore, the absence of the above additional construction cost liability is confirmed.

② The Defendant, in violation of the contractor’s duty of care, constructed a child care center in breach of the standards for establishment of child care centers.

As a result, the Plaintiff received corrective orders for the violation of the standards for the establishment of child care centers (the installation of a kitchen, etc. in a building without a force extension), and reconstructed after all removal.

Therefore, the defendant is obliged to pay KRW 33,200,000 for the cost of demolition and reconstruction due to the nonperformance of obligation.

③ The cost of repairing defects of KRW 3,477,195 is required due to defects in interior works.

Therefore, the defendant is obliged to pay 3,477,195 won as compensation in lieu of defect repair.

④ Claim for principal lawsuit: Claim for KRW 36,67,195 in the aggregate of KRW 33,220,00 and KRW 3,477,195 in confirmation of the absence of any liability for additional construction cost.

At the request of the plaintiff, the defendant made additional construction, such as the change of material, the teachers' room, the data room, and the play room.

Since there exists a separate agreement on the payment of the changed or additional construction cost, the plaintiff is obligated to pay the additional construction cost of KRW 29,707,031 (amount according to the result of appraisal).

Even if there is no additional construction agreement, the defendant who is a merchant can exercise the right to claim remuneration as prescribed by Article 61 of the Commercial Act, so the plaintiff shall pay the said additional construction cost.