Any building, structure or premises lawfully existing at the time of the adoption of this chapter or lawfully existing at the time this chapter is subsequently amended may continue to be used even though such building, structure or premises does not conform to uses, dimensions or other requirements of the zone in which it is located, subject to the provisions of §§ 164-136 and 164-137.

An existing use or building located in a zone in which such use or building is classified herein as a special exception may continue as though it were an authorized special exception but may not be changed or enlarged without further authorization as for a new special exception by the Board.

In the C-B Central Business Zone, a special exception granted by the Board of Appeals on or before May 15, 1995, but which has subsequently been eliminated as a special exception use in that Zone, shall not be regarded as a nonconforming special exception and may be continued, repaired, reconstructed, structurally altered, extended or enlarged in accordance with all City approvals.

In the C-B Central Business Zone, any permitted use which was lawfully existing prior to May 15, 1995, but which has subsequently been eliminated as a permitted use in that Zone, shall not be regarded as a nonconforming use and may be continued, repaired, reconstructed, structurally altered, extended or enlarged in accordance with all City approvals.

A nonconforming use may be extended throughout those parts of a building or structure which were specifically designed or constructed for such use prior to the adoption of this chapter and which parts were either completed or substantially completed, structurally, at the time of adoption of this chapter.

If no structural alterations are made, the Board may approve the changing of a nonconforming use of a building, structure or premises to another nonconforming use if the Board finds that such new nonconforming use is of the same or more appropriate use or more restrictive use. However, no building or premises in which a nonconforming use has been changed, in whole or in part, to a more restricted use shall again be devoted to a less restrictive use.

Except as provided in Subsection C below, no building, structure or premises where a nonconforming use has ceased to operate for six months or more shall thereafter be used except in conformance with this Zoning Ordinance.

Nothing in these regulations shall prevent the restoration of a nonconforming building or structure destroyed by fire, windstorm, flood, explosion or act of the public enemy or accident or prevent the continuance of the use thereof as it existed at the time of such destruction, provided that a zoning certificate is obtained and restoration begun within one year of such destruction. The Zoning Administrator may, upon application of a property owner and upon a finding of good cause, extend the period of time for obtaining a zoning certificate and beginning restoration under this subsection for an additional one-year period.

Any main building which was specifically designed and constructed before November 6, 1979, for a use not permitted by this chapter in the zone in which such building is located shall not be deemed to have lost its nonconforming status unless the nonconforming use of the building shall have ceased for 48 consecutive months or more.