Any use or structure existing at the time of enactment or subsequent amendment of this chapter, but not in conformity with its provisions, may be continued with the following limitations. Any use or building which does not conform to this chapter may not be:

(1)

Changed to another nonconforming use;

(2)

Re-established after abandonment. Discontinuance of a nonconforming use for a period of one year shall be prima facie evidence of such abandonment;

(3)

Enlarged, increased, replaced or removed, except in conformity of this chapter;

(4)

Rebuilt after damage exceeding 50 percent of its replacement cost immediately prior to damage; or

(5)

Continued beyond the periods set forth in section 11-20.