The lawful nonconforming structure existing at the time of the
adoption or amendment of this chapter may be continued although its
size or location does not conform with the lot width, lot area, yard,
height, parking and loading, and access provisions of this chapter.
However, it shall not be extended, enlarged, reconstructed, moved
or structurally altered except when required to do so by law or order
or so as to comply with the provisions of this chapter.
Once a nonconforming use or structure has been changed to conform,
it shall not revert back to a nonconforming use or structure. Once
the Board of Zoning appeals has permitted the substitution of a more
restrictive nonconforming use for an existing nonconforming use, the
substituted use shall lose its status as a legal nonconforming use
and become subject to all the conditions required by the Board of
Zoning Appeals.
A setback less than the setback required for the appropriate
class of highway may be permitted where there are at least five existing
main buildings within 500 feet of the proposed site that are built
to less than the required setback. In such cases, the setback shall
be the average of the nearest main building on each side of the proposed
site or, if there is no building on one side, the average of the setback
for the main building on one side and the required setback. Structures
are permitted in any district but not until their principal structure
is present or under construction.