In the case of a sale of a unit where delivery of an offering statement is required or a disclosure is made pursuant to Section 35-8A-407, a contract of sale may be executed, but no interest in that unit may be conveyed, or voted until the declaration is recorded and the unit is substantially completed, as evidenced by a recorded certificate of substantial completion executed by an independent registered architect, or independent registered engineer, or by issuance of a certificate of occupancy authorized by law.