The regulations specified in this chapter shall be subject to the following exceptions, modifications, and interpretations:

   1.   Use of Existing Lots of Record. In any district where residential dwellings are permitted, a residential dwelling may be located on any single lot or plot of official record as of the effective date of this Zoning Ordinance which does not meet area and or width requirements of this chapter, provided that the following conditions are met:

      A.   The sum of the side yard widths of any such lot or plot shall not be less than 25 percent of the width of the lot, but in no case less than 10 percent of the width of the lot for any one side yard.

      B.   The depth of the rear yard of any such lot need not exceed 20 percent of the depth of the lot, but in no case shall be reduced below 20 feet.

      C.   Zoning compliance permit shall not be issued for construction on any substandard lot, which lot was of record at the time of adoption of this Zoning Ordinance, if said lot is adjacent to and has continuous frontage with any other lot which at the time of the adoption of this Zoning Ordinance was in the same ownership or whose ownership had beneficial interest in said lot, unless said lots are combined into one lot meeting the requirements of the Zoning District which is applicable.

   2.   Structures Permitted Above the Height Limit.  Building height limitations of this chapter shall be modified as follows:

      A.   Chimneys, cooling towers, elevator bulkheads, fire towers, monuments, stage towers or scenery lofts, water towers, grain elevators, ornamental towers and spires, radio or television towers, or necessary mechanical appurtenances may be erected to a height in accordance with existing or hereafter adopted ordinances of the City.

      B.   Public, semi-public, or public service buildings, hospitals, sanitariums, schools, churches, and temples, when permitted in a district, may be erected to a height not exceeding 125 feet, if the building is set back from each property line at least 1 foot for each foot of additional building height above the height limit otherwise provided in the district in which the building is located.

   3.   Area Requirements. In any residential district, where neither public water supply nor public sanitary sewer is accessible, the lot area and frontage requirements shall be:

      A.   Lot area per dwelling units – 20,000 square feet;

      B.   Lot width at building line – 100 feet;

provided, however, that where a public water supply system is available, these requirements shall be 15,000 square feet and 80 feet respectively.

   4.   Double Frontage Lots. Building on through lots extending through from street to street shall provide the required front yard on both streets.

   5.   Other Exceptions to Yard Requirements. Every part of a required yard shall be open to the sky, unobstructed with any building or structure, except for a permitted accessory building in a rear yard.

   6.   Mixed-Use Yard Requirements.  In instances where buildings are erected containing two or more uses housed vertically, the required side yards for the first floor use shall control.