All permits issued prior to the enactment of this chapter for buildings or structures which are contrary to the provisions of this chapter shall be null and void unless substantial work has been done toward the completion of said building or structure. If any of the above requirements shall not have been fulfilled within one year, as stated in Article
IV, §
66-6F(6) above, or if building operations are discontinued for a period of six months, any other construction shall be in conformity with the provisions of this chapter.