No structures or lot shall be used, no existing structure shall be
erected, added to, or structurally altered until a permit therefor
as specified herein has been issued by the Code Enforcement Officer.
Except on written order of the Code Enforcement Officer, no such building
permit shall be issued for any structure where said construction,
addition, or alteration or use thereof would be in violation of any
of the provisions of this chapter or other applicable local laws;
except that structures and uses legally existing at the enactment
date of this chapter shall not require a building permit.