Whenever they shall have reasonable cause to suspect a violation of any provision of this Code, or when necessary to investigate an application for or revocation of any approval under any of the procedures prescribed in this Code, officials responsible for enforcement or administration of this Code, or their duly authorized representatives, may enter on any site or structure for the purpose of investigation, provided they shall do so in a reasonable manner. No premises shall be entered without first attempting to obtain the consent of the owner or occupant. If consent cannot be obtained, the responsible official shall secure a search warrant from the court of competent jurisdiction before further attempts to gain entry and shall have recourse to every other remedy provided by law to secure entry.