A nonconforming use of a building or land may be extended
up to 25% of the area occupied by such use at the effective date of
this chapter, June 25, 1979, when authorized by the Zoning Board of
Adjustment. Any such extension or enlargements shall be immediately
adjacent to the existing nonconforming use, shall be located on the
lot held in a single and separate ownership on June 25, 1979, and
shall conform to the area and height regulations of the district in
which it is situated.