Any nonconforming use, building or structure which lawfully existed at the time of adoption of this chapter may be continued, and any such existing nonconforming building or structure may be reconstructed or structurally altered, provided that it meets with the requirements of this article.

Any structure, or portion thereof, declared unsafe by the Construction Code Official must be restored to a safe condition. This work must be accomplished within 30 days after written notice to the owner and completed to the satisfaction of the Construction Code Official.

There shall be no structural alterations made to any nonconforming building or structure that is nonconforming because of use. Structural alterations may be made in a building which is nonconforming because it fails to comply with height, area, yard, off-street parking or other like requirements of this chapter, as long as the structural alteration does not extend or enlarge the nonconformance.

Nothing in this chapter shall prevent the restoration of a nonconforming building partially destroyed by fire, explosion, act of God or act of public enemy or prevent the continuance of the use of such building, or part thereof, as such use existed at the time of such partial destruction of such building, or part thereof, or prevent a change of such existing use under the limitations provided herein.

Once changed to a conforming use, no building or land shall be permitted to revert to a nonconforming use.

Whenever a nonconforming use has been abandoned, such use shall not thereafter be reestablished, and any future use shall be in conformity with the provisions of this chapter.