Any nonconforming use which existed lawfully at the time of adoption of this chapter may be continued, subject to the following provisions:
A. 
Expansion. A nonconforming use or building may be enlarged or extended up to 25% beyond the area occupied by such use at the time of the adoption of this chapter, subject to a special use permit issued by the Planning Board.
B. 
Modification. A nonconforming use shall not be changed to any other nonconforming use, nor shall a nonconforming use be changed to any other use unless such change is of the same or a less nonconforming nature and only with prior approval by the Planning Board.
C. 
Replacement. If a nonconforming use is replaced by another use, such use shall be required to conform to this chapter.
D. 
Destruction. If any building or structure in which a nonconforming use is conducted is hereafter damaged or destroyed by fire, wind, explosion, structural failure or other natural cause, up to 50% of its value, it may be repaired or reconstructed, and the use reinstated, so long as the nonconformity is not increased or expanded and if all necessary building permits are obtained within three years.
E. 
Discontinuance. If a nonconforming use is discontinued for a period of 12 consecutive months, it shall expire, and any subsequent use on that lot shall conform to the regulations of the district in which it is located.
Where a lawful building or structure exists at the effective date of adoption or amendment of this chapter that could not be built under such adoption or amendment by restriction on the lot area, lot coverage area, height, yards or other characteristics of the structure or its location on the lot, such structure may be maintained so long as it remains otherwise lawful, subject to the following provisions:
A. 
Expansion. Nothing in this chapter shall prevent the strengthening or alteration to a safe condition of all or part of a building or structure that is nonconforming, provided that the repair or alteration will not increase the height, size or volume of the building or structure or otherwise increase the nonconformity.
B. 
Additions, alterations, maintenance and repairs.
(1) 
A nonconforming building or structure shall not be added to or enlarged or altered in any manner in a way which increases its nonconformity.
(2) 
Should such structure or building be moved for any reason, it shall thereafter conform to the regulations for the district in which it is located after it is moved.
(3) 
A nonconforming building or structure is hereby required to be maintained in such condition as will not constitute a danger to the health, safety, or general welfare of the public. The nonconformance alone of a building or structure shall not be construed as constituting such a danger.
(4) 
A single-family dwelling may be enlarged or rebuilt to within the dimensional provisions of the district where it is located.
C. 
Discontinuance.
(1) 
A nonconforming building or structure, or a portion thereof, shall be deemed discontinued if the building or structure is vacant for 12 consecutive months.
(2) 
If deemed discontinued, such building or structure shall not be reestablished, and any subsequent use shall not commence until the building or structure is brought into conformity with the provisions of the district in which it is located.
D. 
Restoration. A nonconforming building or structure destroyed or damaged by fire, wind, explosion, structural failure, or other natural cause may be repaired or reconstructed, so long as the nonconformity is not increased or expanded, if all necessary building permits are obtained within three years.
E. 
Completion of substantially constructed structures. Nothing contained in this chapter shall require any change in plans, construction, alteration or designated use of a structure for which substantial construction work has lawfully commenced prior to the adoption of this chapter.
Any lot held in single and separate ownership, for which a map was filed or a deed recorded prior to the adoption of this chapter, whose area and/or width is less than the specified minimum lot requirements of this chapter for the district in which it is located may be considered as complying with such minimum lot requirements, and no variance shall be required, provided that:
A. 
It does not adjoin other land, held by the same owner, whose aggregate area is equal to or greater than the minimum lot area required for that district.
B. 
All other bulk and yard requirements for that district are complied with to the maximum extent practicable.