Where a lawful use or structure exists which, on the effective date of this chapter or subsequent amendment thereto, becomes nonconforming, such use or structure may be continued as long as it remains otherwise lawful, including subsequent sales of the property, subject to the following provisions:
A. The existing nonconforming use shall not be changed to a different nonconforming use.
B. No such nonconforming use or structure shall be altered or extended except if such complies with the following criteria and standards:
(1) To provide for a natural expansion which is not detrimental to public health, safety, and general welfare, provided such expansion does not exceed 50% of the existing ground floor area of the structure or other space occupied by the use;
(2) Provided such does not constitute the addition of a new nonconforming use or structure;
(3) Provided such does not decrease yard setbacks when such already fail to meet minimum yard setback areas; and
(4) Provided that the alteration or extension meets the district regulations for such use or structure as if same were being altered or extended in district where such use is permitted. In cases where the use is permitted in two or more districts, the most restrictive district regulations shall apply.
C. In the event that any nonconforming structure is destroyed or partially destroyed by any means to an extent of 75% or more of the replacement value less depreciation of such structure immediately preceding the casualty, such nonconforming structure and use thereof shall terminate and the lot shall thereafter be used only for conforming uses and structures.
D. When a nonconforming use or structure is discontinued or abandoned for a period of one year or more continuously, or replaced by a conforming structure, the premises shall not thereafter be used except in conformity with the regulations of the district in which it is located, except if the use is a farm use as herein defined.