No building or structure shall be used or occupied, and no change in the existing occupancy classification of a building or structure or portion thereof shall be made until the building official has issued a certificate of occupancy therefor. Issuance of a certificate of occupancy shall not be construed as an approval of a violation of the provisions of any code or any ordinances of the city. Certificates presuming to give authority to violate or cancel the provisions of any code or ordinances of the city shall not be valid. [Code 2000 § 18-1-5].