1. All appeals filed by the Defendant (Counterclaim Plaintiff) against the instant principal lawsuit and counterclaim are dismissed.

2. The costs of appeal shall be the principal lawsuit.

1. Basic facts

A. 1) The Defendant is operating the Do solid shop located in Gangnam-si C. 2) The Defendant was planning to construct a closed compressed machine room in order to install a new closed compressed machine in Gangnam-si G, which is a F solid site for the operation of E around August 2017.

B. Accordingly, on August 2017, the Defendant ordered the Plaintiff to install the compressed machine room.

(hereinafter the above mechanical room "the instant mechanical room" and the above installation work "the instant installation work" C.

From September 1, 2017 to July of the same month, the Plaintiff performed the structural frame and roof structure construction of the instant mechanical room (hereinafter “the primary construction”). D.

The Plaintiff received KRW 7,600,000 in total from the Defendant on August 29, 2017, plus KRW 2,600,000 in remainder on September 8, 2017.

E. Since September 19, 2017, from September 27, 2017 to September 27, 2017, the Plaintiff (i) performed a side lag and a wall-frameing construction work (hereinafter “second lag construction”) with the content of performing the wall structure of the board board lecture on the roof constructed by the primary construction.

F. (1) On September 29, 2017, the Plaintiff sent a text message to the Defendant on September 28, 2017, including both the details of the first and second construction works. (2) After requesting the Plaintiff to make a written estimate, the Plaintiff sent a text message to the Defendant on September 28, 2017. (3) On the same day, at around 17:18, the Plaintiff sent a text message to the Defendant on September 18, 201. (4,114,00 won) and the written estimate of the second construction works.

G. On November 14, 2017, the Plaintiff sent a written estimate on “the details of the secondary construction works” to the Defendant on September 29, 2017, but did not pay the construction cost even after 40 days.

Accordingly, upon the plaintiff's request for the construction cost, the defendant did not pay the construction cost excessively around November 6, 2017.

It is merely a unilateral argument that the construction price of KRW 4,114,00 for the secondary construction, which is an additional construction, will be paid until November 20, 2017.

“The content certification was sent.”

【Ground of recognition】 The fact that there is no dispute, A, Nos. 1, 4, 5, 6, 7, 8.