Ohio Rev. Code Ann. § 4733.161 – Unauthorized practice

(A) Notwithstanding any other provision of this chapter, any person who performs labor or who provides services pursuant to a construction contract may offer or provide engineering services in connection with the person's own labor or services if all of the following apply:
1. (1) The engineering services are provided and performed by an engineer registered under this chapter or by a firm holding a certificate of authorization granted pursuant to this chapter through either direct employment or independent contract with the person contracting with the owner and offering the services.
2. (2) The engineering services are offered by the person who intends to perform the actual construction of an improvement to real property as part of a design-build contract.
3. (3) The contractor, the engineer registered under this chapter, or the firm holding a certificate of authorization granted pursuant to this chapter meets the requirements of section 153.70 of the Revised Code when design-build services are provided to a public authority as defined in section 153.65 of the Revised Code.
(B) Except as otherwise provided in this section, no person shall offer or engage in the practice of engineering without a certificate of authorization for any construction contract that is to be constructed by another person, or hold himself or herself out to the public as engaging in the practice of engineering or as providing engineering services without a certificate of authorization.
(C) As used in this section, "construction contract" and "design-build" have the same meaning as in section 4703.182 of the Revised Code.