1. As to the Defendant’s ground of appeal

A. In a case where a contractor is obliged to settle construction costs due to the rescission of a construction contract without completion of the construction work, the construction cost shall be calculated by applying the agreed construction cost to the agreed construction cost by applying the ratio of the completed part and the construction cost calculated based on the construction cost actually required or to be required for the non-construction part. The completed part shall be the ratio of the construction cost to the total construction cost incurred for the completed part of the total construction cost. If the design and specifications are modified in the construction contract, the construction cost shall be calculated by applying the ratio of the changed construction cost to the total construction cost (see, e.g., Supreme Court Decision 200Da4095, Feb. 26, 2003). If the design and specifications are modified in the construction contract, the construction cost shall be calculated by applying the ratio of the changed construction cost to the changed construction cost due to the design and specifications (see, e.g., Supreme Court Decision 200Da4095, Feb. 26, 2003).

B. According to the reasoning of the judgment below, based on Article 19 of the Construction Contract in this case as indicated in the judgment of the court below, the construction contract in this case was based on the premise that the construction contract in this case is permitted to adjust the amount of the construction contract due to design modification, and all of the construction works modified in the course of the design design or construction implementation as indicated in the judgment of the court below are deemed additional construction works due to design modification as stated in the construction contract in this case. Thus, if the construction contract amount is calculated by reflecting the modified contents, the construction contract amount shall be 2,867,310,00 won (excluding value-added tax). Meanwhile, the fixed rate of 1,529,090,000 won up until the discontinuance of the construction work in this case is 1,824,980,980,000 won + 1,437,8980,000 won and 409,0000 won (excluding value-added tax).

C. Examining the relevant legal principles and records, the lower court’s determination that the part of construction works executed by the Plaintiff according to the starting drawing constitutes additional construction due to modification of design as stipulated in the instant construction contract is just and acceptable. In so doing, it did not err by exceeding the bounds of the principle of free evaluation of evidence against logical and empirical rules, or failing to exhaust all necessary deliberations.

D. However, it is difficult to accept the lower court’s calculation of the price for the construction work as above for the following reasons.

The lower court recognized the construction amount calculated on the basis of the starting drawings by applying the unit price stated in the written estimate included in the instant construction contract (hereinafter referred to as "contract unit price") as the adjusted construction contract amount according to the design modification.

However, Article 19 (2) of the Construction Contract of this case seems to have decided on the price of the increased or decreased construction rather than the new calculation of the total amount of the construction contract in the case of the modification of design.

Therefore, the part of the changed design and specifications was determined in preparation for the permit drawings that form the basis of the instant construction contract and the changed design drawings, and then the construction cost of the changed part shall be calculated by adding it to the original construction contract amount by the method stipulated in Article 19(2) of the instant construction contract and adding it to the construction cost of the original construction contract, and the amount of the construction contract after design modification shall have been calculated by applying the formula and ratio thereto.

First of all, there is a lack of evidence to acknowledge that the Plaintiff and the Defendant agreed to increase the contract amount of the instant construction contract as to the original construction contract amount of KRW 1,440,00,000 (excluding value-added tax), which is the contract amount of the instant construction contract. As such, the contract amount of the instant construction contract based on the permissible drawings ought to be deemed as KRW 1,440,000,000.

In addition, as stipulated in Article 19(2) of the Construction Contract of this case, the Plaintiff and the Defendant did not have determined the unit price by mutual consultation based on the contract unit price. As such, the difference between the construction cost calculated by applying the contract unit price and the contract unit price calculated by applying the contract unit price to the construction cost pursuant to the starting drawing shall be deemed the additional construction cost to comply with the permitted drawing. The difference between each construction cost calculated as above according to the appraisal by the appraiser H of the lower court is KRW 197,550,00 (value-added tax separate). Thus, the increased construction cost by changing the design, such as the starting drawing, can be deemed as

Thus, 1,440,00,000 and additional construction costs of KRW 1,637,550,00,000, which are the total construction cost of KRW 1,637,550,000, multiplied by 780,783,840 (the construction cost rate calculated according to the construction cost based on the starting drawings based on the contract unit cost), which is the total amount of KRW 858,862,224, which is the total value-added tax, shall be the construction cost of KRW 858,862,224, which is the total value-added tax, and since the construction cost that the Defendant paid to the Plaintiff is KRW 942,90,000,00, the construction cost that the Defendant paid to the Plaintiff is not remaining.

Nevertheless, the court below partially accepted the plaintiff's claim on the premise that the plaintiff has a claim for construction cost to be paid, which is erroneous in the misapprehension of legal principles as to the calculation of construction cost due to the modification of design.

2. Plaintiff’s ground of appeal

As seen earlier, the Plaintiff’s assertion purporting that the calculation of the compensation for delay is unreasonable is not acceptable, since it is not necessary to determine the offset base based on the Defendant’s claim for compensation for delay, as long as the Plaintiff cannot recognize the claim for construction payment based on

3. Conclusion

Therefore, without further proceeding to decide on the remaining grounds of appeal by the Defendant, the part against the Defendant among the judgment below is reversed, and that part of the case is remanded to the court below for further proceedings consistent with this Opinion. The Plaintiff’s appeal is dismissed. It is so decided as per Disposition by the assent of all participating Justices on

Justices Kim Gin-young

Chief Justice Lee Dong-won