All buildings erected hereafter, all uses of land or buildings established hereafter, any structural alteration or relocation of existing buildings occurring hereafter shall be subject to all regulations of this Ordinance which are applicable to the zoning districts in which such buildings, uses, and land shall be located. However, where a building permit for a building or structure has been issued in accordance with law prior to the effective date of this Ordinance and provided that construction is begun within (6) months 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 has been issued, and further, may upon completion be occupied under a certificate of occupancy by the use for which originally designed--subject thereafter to the provisions of Chapter 1149
, Nonconforming Buildings, Uses and Structures.