Ohio Rev. Code § 3781.02
The provisions prescribing the minimum distance at which buildings or structures shall be located from any lot line or the provisions relating to open courts and fireproof passageways do not apply when Chapters 3781. and 3791. of the Revised Code or the rules and regulations of the board of building standards are, or can be, complied with by or with the use of adjoining property, and when such adjoining property affords the widths and areas as prescribed by such chapters or the rules and regulations of the board of building standards and is available for the purposes intended, and when such adjoining property is so situated, used, dedicated, or deeded as to preclude the erection of any building or structure or part thereof on the widths and areas so used, during the existence of the building or structure.
R.C. §3781.02