1. The defendant's appeal is dismissed.

2. The costs of appeal are all borne by the Defendant, including those resulting from the supplementary participation.

1. Basic facts

A. On November 27, 2013, the Plaintiff concluded a contract for fire-fighting system installation works (hereinafter “instant construction contract”) with a corporation established for the purpose of the management of fire-fighting systems and construction business, etc., and with A, with respect to the fire-fighting system installation works of the ASEAN-si Building (hereinafter “instant wedding building”) owned by it, the construction cost of KRW 245,000,000 (excluding value-added tax) and the construction period of the instant wedding building was determined from November 27, 2013 to May 31, 2014.

On the same day, Co-Defendant B of the first instance trial (hereinafter referred to as “B”) jointly and severally guaranteed the A’s obligation to pay the construction price under the instant construction contract.

B. On August 2014, the Plaintiff entered into an agreement with A and B regarding the instant construction contract (hereinafter “instant agreement”) with the following terms and conditions (hereinafter “instant agreement”).

In relation to the instant construction contract, the Plaintiff shall conduct fire-fighting system installation works at the Plaintiff’s expense, but A and B shall pay to the Plaintiff KRW 269,50,000 (including value-added tax) within one month after completion of the said construction works.

As to the payment method of the above construction cost, consultation shall be made as follows:

1. Within ten days after the completion of fire-fighting system installation works for the wedding building in this case, A and B shall apply for loans to financial institutions as security;

2. A and B shall cooperate with the Plaintiff to pay directly the amount of 269,50,000 won out of the loan extended in consultation with the financial institution at the time of the application for the above loan. If the agreement is not complied with, A and B shall pay to the Plaintiff 269,50,000 won per annum from the completion date of fire-fighting system installation to the full payment date.

C. On October 14, 2014, the Plaintiff completed all fire-fighting system installation works on the instant wedding building in accordance with the instant construction contract and agreement, and on December 2, 2014, approved the use of the said building.

A and B shall pay the construction cost of KRW 269,50,000 to the Plaintiff according to the instant construction contract and agreement.