Any use of any building, structure or land existing on January 1, 1959, may be continued even though such use does not conform to the provisions of this chapter, so long as said use as of January 1, 1959, had been in existence and constantly maintained for a period of five years.

Any structure or building or portion thereof declared unsafe by a proper authority may be restored to meet safety requirements if the cost of such restoration does not exceed 50% of the value of the building or structure at the time of such declaration.

Any building or structure may be restored or repaired in the event of destruction; provided, however, that such restoration or repair is completed within one year of the date of the destruction thereof.

Nothing in this chapter shall prevent the repairing of a nonconforming use or structure, or part thereof, existing on January 1, 1979, rendered necessary by wear and tear, deterioration or disrepair, provided that the cost of such work shall not exceed 50% of the value of such building or structure at the time such work is to be done.

No existing structure in which there is a nonconforming use shall be expanded either in square feet nor in cubic feet either vertically or horizontally, nor shall the existing building envelope be expanded in any direction. Any departure from the provisions of this section shall require the submission of a variance application to the Board of Adjustment pursuant to the provisions of N.J.S.A. 40:55D-70(d).