Any erection, construction, reconstruction, alteration or moving of the building or other structure, including a sign, authorized by a zoning permit shall be commenced, and any change in use of a building or land authorized by a zoning permit shall be undertaken, within six months after the date of issuance of the permit. If not, the permit shall be considered null and void. However, in case of erection or construction of a building, the right to proceed with construction may be extended annually without payment of additional fee for an aggregate period of not more than three years, provided that the construction pursuant to said permit has commenced within the first six months.