Unsafe structures. Subject to the provisions set forth below, any structure or portion thereof declared unsafe by a proper Village authority may be restored to a safe condition.

Alterations. A nonconforming building may not be reconstructed or structurally altered during its life to an extent exceeding in aggregate cost 50% of the assessed value of the building unless said building is changed to a conforming use.

Extension. A nonconforming use shall not be extended, but the extension of a lawful use to any portion of a nonconforming building which existed prior to the enactment of this chapter shall not be deemed the extension of such nonconforming use.

Restoration. No building damaged by fire or other causes to the extent of more than 75% of its assessed value shall be repaired or rebuilt except in conformity with the regulations of this chapter.

Changes. Once changed to a conforming use no building or land shall be permitted to revert to a nonconforming use. A nonconforming use may be changed to a use of the same or higher classification, and such use thereafter shall not be changed to a lower classification.

Displacement. No nonconforming use shall be extended to displace a conforming use.

Cessation. Notwithstanding any other provisions of this chapter, any automobile wrecking yard or other junkyard in existence in any zone district at the date of enactment of this chapter shall at the expiration of three years from such date become a prohibited and unlawful use and shall be discontinued.

District changes. Whenever the boundaries of district shall be changed so as to transfer a lot or lots from one district to another district of a different classification, the foregoing provisions shall also apply to any nonconforming uses existing therein.