1. The plaintiff's claim is dismissed.

2. The costs of lawsuit shall be borne by the Plaintiff.

1. Basic facts

A. On August 13, 2013, the Plaintiff and the Defendant concluded each contract with respect to the housing remodeling construction works located in Geumcheon-gu Seoul Metropolitan Government (hereinafter “instant construction works”), setting the construction cost of KRW 329,00,000 (the contract amount of KRW 30,000,000, and the progress payment of KRW 20 days within the limit of the completion of the construction works), the construction period from August 15, 2013 to November 15, 2013, with respect to the construction works located in Geumcheon-gu Seoul Metropolitan Government (hereinafter “instant construction works”).

B. Around 2014, the Plaintiff completed the instant construction project, including additional construction work equivalent to KRW 19,250,000, and the Defendant paid KRW 311,600,000 in total from August 13, 2013 to April 12, 2014.

[Ground of recognition] Facts without dispute, entry of Gap evidence 1 to 5, purport of the whole pleadings

2. The assertion and judgment

A. The Plaintiff’s assertion 1) The Defendant is obligated to pay the Plaintiff the additional construction cost of KRW 36,650,000 (i.e., KRW 329,00,000 for the instant construction cost of KRW 19,250,00 for the fixed payment - KRW 311,60,000 for the fixed payment) and damages for delay thereof. The Defendant’s assertion 2) as follows: (i) the Plaintiff’s assertion that the instant construction cost occurred after the instant construction work and the rooftop water, and requested the Plaintiff to pay the remuneration several times, but the additional waterproof construction cost of KRW 7,00,00 for the lack of payment. By April 23, 2018, the Defendant paid KRW 26,087,90 for construction enforcement money due to the non-permitted rooftop building.

② From April 12, 2014, the date of the Plaintiff’s payment of the final construction price, the short-term extinctive prescription of the instant claim for the construction price was completed.

B. 1) Determination 1) There is no dispute between the parties on the facts that the unpaid price for the instant construction project was 36,650,000 won, and the Defendant’s defense is examined. 2) Determination as to the offset claim is based on the Defendant’s counterclaim. The Defendant’s claim amounting to KRW 26,087,90,000, which was additionally paid, and the amount of construction enforcement charge imposed on the rooftop warehouse building.