Additions. A nonconforming building or use shall not be added to or enlarged unless such nonconforming building or use is made to conform to the regulations of the district in which it is located.

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

Changes. A nonconforming use may be changed to another nonconforming use of the same or higher classification according to the provisions of this chapter and when so changed such use shall not thereafter be changed to a nonconforming use of a lower classification.

Discontinuance. Whenever a nonconforming use has been discontinued for a period of one year, any future use shall be in conformity to the provisions of this chapter.

Restoration. A building nonconforming as to use which has been damaged by fire or other causes to the extent of not more than 50% of its fair value may be restored, reconstructed or used as before, provided the bulk, height, and area requirements shall not exceed that which existed before said damage. Said restoration must be completed within one year of such occurrence or the use of the building or land as a legal nonconforming use thereafter shall be terminated.

Removal. If any building in which any nonconforming use is conducted is hereafter removed, the subsequent use of the land on which such building was located and the subsequent use of any building erected thereon shall conform with the regulations of the district.

Validity of permit. Any building for which a permit has been lawfully granted, and on which the construction has been started and diligently prosecuted before the effective date of this chapter or any amendment hereto may be completed.