The off-street parking and loading requirements of this Ordinance shall apply as follows:
(a) For all buildings and structures erected and all uses of land established after the effective date of this Ordinance, accessory parking and loading facilities shall be provided as required by the regulations of the district in which such buildings or uses are located. However, where a building permit has been issued prior to the effective date of this Ordinance and provided that construction is begun within 6 months of such effective date and diligently pursued to completion, parking and loading facilities in the amounts required for the issuance of said building permit may be provided in lieu of any different amounts required by this Ordinance.
(b) When the intensity of use of any building, structure, or premises shall be increased through the addition of dwelling units, gross floor area, seating capacity, or other units of measurement specified herein for required parking and loading facilities, parking and loading facilities as required herein shall be provided for such increase in intensity of use and for at least 50 percent of any existing deficiency in parking or loading facilities.
(c) Whenever the existing use of a building structure shall hereafter be changed to a new use, parking or loading facilities shall be provided as required for such new use. However, if the said building or structure was erected prior to the effective date of this Ordinance, additional parking or loading facilities, are mandatory only in the amount by which the requirements for the new use would exceed those for the existing use, if the latter were subject to the parking and loading provisions of this Ordinance.