Where a lawful structure exists, at the effective date of adoption or amendment of the ordinance from which this chapter is derived, that could not be built under the terms of this chapter by reason of restrictions on area, lot coverage, height, yards, its location on the lot, or other requirements concerning the structure, such structure may be continued as long as it remains otherwise lawful, subject to the following provisions:
(a) No such nonconforming structure may be enlarged or altered in a way which increases its structural nonconformity, but any structure or portion thereof may be altered to decrease its structural nonconformity.
(b) Should such nonconforming structure or nonconforming portions of structure be damaged by any means to an extent of more than 50 percent of its replacement cost at the time of destruction, it shall not be reconstructed except in conformity with the provisions of section
138-43 of this chapter.
(c) Should such structure be moved for any reason for any distance whatsoever, it shall thereafter conform to the regulations of the district in which it is located after it is moved.
(1966 Code, § 32-10)