Before proceeding with the excavation for the erection of, or the repair, enlargement or removal of any building or structure within the city, a permit must first be obtained from the building department. If the operations allowed under such permit are not begun within six (6) months thereafter, such permit shall become null and void, and if such work is resumed a new permit must be obtained and the regular fee incident thereto shall be collected. The responsibility of obtaining such permit shall be shared jointly with the owner of the premises, his agent, and the builder or contractor erecting the improvement, and either or both are subject to the penalty imposed upon failure to obtain such permit. (1983 Code)