1. Basic facts

A. On October 23, 2013, the Plaintiff entered into a contract with the Defendant under which the construction of the instant building C (hereinafter “instant building”) was to be supplied (hereinafter “instant construction contract”).

B. On January 1, 2014, the Plaintiff completed the instant construction and delivered the instant building to the Defendant. On January 16, 2014, the Defendant completed registration of initial ownership relating to the instant building.

C. While the floor area on the first drawing of the instant building was 98.1 square meters, the building area of the approval for use after the completion of the new construction of the instant building is 110.7 square meters.

The Defendant paid the Plaintiff KRW 90,000,000 in total as the construction cost of the instant case.

[Reasons for Recognition] Facts without dispute, Gap evidence Nos. 1, 2, 13, 14, Eul evidence Nos. 11 and 12, the purport of the whole pleadings

2. Determination on the main claim

A. The Plaintiff agreed to newly construct the instant building at KRW 3,500,000 per square meter, and the instant building at KRW 33 square meters. Thus, the total amount of the original construction cost is KRW 115,500,000.

B) The Plaintiff, as additional construction, constructed a retaining wall and an indictment for late 12 square meters [12 square meters x 600,000 won] 2. 8,094,500 won for additional construction work for reinforcement of internal heat (2,094,500 won for construction work) 3. 757,000 won for material cost (27,000 won for 871,000 labor cost, 660,000 won for material cost) . The Defendant paid 757,000 won for boiler price to be paid by the Plaintiff on behalf of the Plaintiff. As such, the Defendant paid 127,082,50 won for total construction cost (=15,500,000 won for construction cost + KRW 115,500,000 for 10,500 for additional construction cost + KRW 7,500,000 for the Plaintiff’s 30,500 won for additional construction cost