Except as otherwise provided herein, any lawfully
established use of a building or land existing at the time of the
enactment of this chapter or amendments thereto may be continued although
such use does not conform with the provisions of this chapter.
The nonconforming use of any building, structure
or portion thereof may be changed, with the approval of the Board
of Appeals, to a use of a more restricted classification, and when
so changed shall not thereafter be changed to a less restricted classification.
Normal maintenance of a nonconforming building
is permitted. However, such building may not be reconstructed or structurally
altered during its life to an extent exceeding in aggregate cost 25%
of the market value of the building unless changed to a conforming
use.
A nonconforming use shall not be extended, but
the extension of a lawful use to any portion of a nonconforming building
designed or manifestly arranged for such use, which existed prior
to the enactment of this chapter, shall not be deemed the extension
of such nonconforming use.
No building damaged by fire or other causes
to the extent of more than 60% of its real value, as computed through
the use of equalization rates current at the time, shall be repaired
or rebuilt except in conformity with the regulations of this chapter.
Whenever the boundaries of a district shall
be changed so as to transfer an area from one district to another
district of a different classification, the foregoing provisions shall
also apply to any nonconforming uses existing therein.