The provisions of this article shall apply to all nonconforming uses or bulk existing on the effective date of this chapter and to use or bulk that become nonconforming by reason of any amendment thereof, and to buildings or other structures housing such uses.

Any nonconforming use or building may be continued indefinitely except as hereinafter provided in this section.

If a nonconforming use is discontinued for an uninterrupted period of two calendar years or more, the building, structure, or lot occupied by such nonconforming use shall immediately thereafter and hence forth be entitled to occupancy only by conforming uses.

A nonconforming use may be changed to a conforming uses at any time, but shall not thereafter be changed back to a nonconforming use.

A nonconforming use may be changed to another nonconforming use by special permit from the Planning Board, if the Board deems the proposed nonconforming use to be similar in nature to the existing nonconforming use or closer in character with surrounding conforming uses than the existing nonconforming use.

A nonconforming use shall not be enlarged or extended or relocated to a different position of the lot which it occupies.

Customary maintenance of a building or other structure containing a nonconforming use is permitted, including necessary nonstructural repairs and minor alterations, so long as they do not increase or expand the nonconforming use.

No structural alterations are permitted in buildings that are nonconforming in use, except when required by law or when adapting or remodeling a building or other structure for a conforming use.

Buildings and structures which are only nonconforming in bulk may be altered, moved, reconstructed, or enlarged provided that such change does not increase the degree of, or create any new, nonconforming bulk in such building and does not violate any other provisions of this chapter.

No lot shall be reduced in area so that it creates a nonconforming bulk or use in violation of any regulations contained in this chapter.

If a nonconforming use or a building or other structure of nonconforming bulk sustains an amount of damage or destruction by any cause, which in amount is officially appraised to be 80% or more of its true value, the building, other structure or tract of land shall thereafter be only eligible for, and only occupied by, a conforming use or structure. The damaged portions of a building or other structure may be rebuilt or reconstructed within one year, so long as the nonconformity is not increased or expanded, if the damage is less than 80% of true value.