1. All incidental appeals by the Plaintiff (Counterclaim Defendant) and the appeal by the Defendant (Counterclaim Plaintiff) are dismissed.

2.The Court.

A principal lawsuit and a counterclaim shall be deemed simultaneously.

1. Facts of recognition;

A. On August 2016, the Plaintiff received a contract from the Defendant for interior works including the three-story fire-fighting systems and toilet works of the third floor E of the D building in Busan-gun, Busan-gun (hereinafter “instant construction”) and completed the instant construction works around September 2016.

B. On January 4, 2017, the Defendant issued an agreement stating that “I will agree to pay the balance of construction cost of KRW 3 million by the end of January 2017” to the Plaintiff, and paid KRW 2 million in total as of January 27, 2017 and KRW 1 million on July 5, 2017.

[Ground of recognition] Gap evidence Nos. 1, 3, 4, Eul evidence Nos. 2, 4-2, and 4, F's testimony of a witness of a party trial, the purport of the whole pleadings

2. According to the above facts of recognition as to the cause of the principal claim, barring special circumstances, the Defendant is obligated to pay the Plaintiff the payment of the construction cost of one million won and the damages for delay.

3. Determination on a defense and a counterclaim against a claim on the principal lawsuit

A. The purport of the defendant's assertion is that the plaintiff is obligated to pay to the defendant the sum of the damages 3.4 million won in lieu of the defect repair pursuant to the fire-fighting system installation works, the sum of the damages 2.3 million won in lieu of the defect repair due to the leakage of drainage facilities, and the damages for delay thereof. The plaintiff is entitled to deduct or offset the claim for construction payment of one million won in lieu of the damages due to the defect repair, and at the same time seek the payment of the total sum of the damages and the damages for delay as a counterclaim.

B. 1) In full view of the purport of the entire arguments in the statement of evidence Nos. 2 and 2-1 of the construction cost, it can be acknowledged that the plaintiff incurred a defect in the fire-fighting system among the parts constructed by the plaintiff after the construction of this case, and that the defendant paid 3.40,000 won to repair the defect. The plaintiff is liable to compensate the defendant for the damages suffered by the defendant due to the above defect, while the plaintiff is liable to compensate for 3.40,00 won.