The case started when Mr. A, who acquired and opened a gym on the second floor of an existing gym, complained about noise from a tenant on the first floor, and the management demanded full soundproofing. Hanbyol Law LLC Attorney Lee explained that according to precedent, a late entrant is required to accept a certain amount of noise from the existing business, and if there is no noise-related special clause in the lease agreement and no request for soundproofing during the acquisition process, there is no basis for the management to force full construction after the fact.

Mr. Hanbyol emphasized that the key issues are the content of the contract, the subtenant's duty of acceptance, and the scope of the arbitration clause in the management agreement. The experts recommended defending goodwill by systematically responding to the management's letter with objective noise measurements to confirm whether the legal standard is exceeded, and by providing proof of content to clarify the lack of legal basis.