Except as provided in §§ 240-79 and 240-80, the lawful use of any building or land existing at the time of the enactment or amendment of this chapter may be continued although such use does not conform to the provisions of this chapter.

When a nonconforming use has been discontinued for a period of one year, such use shall not thereafter be reestablished, and any future use shall be in conformity with the provisions of this chapter.

No nonconforming use shall be changed to other than a conforming use for the district in which it is situated. Once changed to a conforming use, no building or land shall be permitted to revert to a nonconforming use.

Any nonconforming structure or part thereof may be restored to a safe condition.

A nonconforming building damaged by fire or other causes may be repaired or rebuilt, provided that the nonconformity shall not be increased and that construction starts within a period of one year. Any unsafe building, however, may be required to be removed within the time frames and in accordance with the provisions of Chapter 94, Buildings, Unsafe, of this Code.

A nonconforming building may be reconstructed or structurally altered only to the extent of its prior nonconformity.

A nonconforming use shall not be extended. The extension of a lawful use to any part of a nonconforming building shall not be deemed the extension of such nonconforming use.

Nothing herein contained shall require any change in plans or construction of a nonconforming building for which a building permit has been issued.