Ohio Revised Code Title XIII. Commercial Transactions § 1311.10

(A) Any person who contracts for an improvement to real property which gives rise to lien rights under sections 1311.01 to 1311.22 of the Revised Code is presumed to be the authorized agent of all part owners of the real property, except when the relationship between the person contracting for the improvement and the other part owners is that of lessee and lessor or sublessee and sublessor.

(B) Any person who contracts for improvements provided in a home construction contract, as defined in section 1311.011 of the Revised Code, is presumed to be the agent for his spouse.

(C) The presumptions established by this section may be overcome only by clear and convincing evidence.