Buildings or other structures shall not be erected, moved, added to, modified or structurally altered without a permit therefor, issued by the Zoning Administrator. Building permits shall be issued in conformance with the provisions of this chapter, or upon written order from the Board of Adjustment. Fees for building permits shall be as provided by Section 165.52 of this chapter. Building permits issued in accordance with the provisions of this section shall be null and void at the end of six months from the date of issue if the construction, alteration, or change of use has not commenced during the six month period. Construction must be completed within two years after the date of the issue of the permit. After the permit has expired, a new permit must be applied for before any further construction can begin or continue.