A. Changes in Structures or Use: Except as may otherwise be provided in Chapter 3 of this Title, all buildings hereafter erected, all uses of land or buildings hereafter established, all structural alterations or relocation of existing buildings occurring hereafter and all enlargements of or additions to existing uses occurring hereafter shall be subject to all regulations herein which are applicable to the zoning districts in which such buildings, uses or land shall be located.
B. Nonconforming Buildings, Structures and Uses: Any lawful building, structure or use existing at the time of the enactment of the zoning ordinance may be continued even though such building, structure or use does not conform to the provisions herein for the district in which it is located; and whenever a district shall be hereafter changed, the then existing lawful use may be continued, subject to the provisions of Chapter 3 of this Title, Nonconforming Buildings and Uses.
C. Building Permits: Where a building permit for a building or structure has been issued in accordance with law prior to the effective date hereof, and provided that construction is begun within ninety (90) days of such effective date and diligently prosecuted to completion, said building or structure may be completed in accordance with the approved plans on the basis of which the building permit was issued, and further may, upon completion, be occupied under a certificate of occupancy by the use for which originally designated, subject thereafter to the provisions of Chapter 3 of this Title, Nonconforming Buildings and Uses.