No existing building or premises devoted to a use not permitted by this chapter in the district in which such building or premises is located, except when required to do so by law or order, shall be enlarged, extended, reconstructed, substituted, or structurally altered unless the use thereof is changed to a use permitted in the district in which such building or premises is located, and except as follows:
(a) Substitution or Extension. When authorized by the Board, in accordance with the provisions of Chapter 1109, the substitution for a nonconforming use of another not more objectionable nonconforming use, or an extension of a nonconforming use, may be made, but not both a substitution and an extension.
(b) Extension on Adjoining Lot. When authorized by the Board, in accordance with the provisions of Chapter 1109, the extension or completion of a building devoted to a nonconforming use on a lot occupied by such building, or on a lot adjoining, may be made, provided that such lot was under the same ownership as the lot in question on the date the use of such building became nonconforming, and where such extension is necessary and identical to the existing use of such building.
(c) Extension Inside Building. When authorized by the Board, in accordance with the provisions of Chapter 1109, a nonconforming use may be extended throughout those parts of a building which were manifestly designed and arranged for such use prior to the date when such use of the building became nonconforming, if no structural alterations, except those required by law, are made therein.
(d) Nonconforming Use Made To Conform. Whenever a nonconforming use has been changed to a conforming use, such use shall not thereafter be changed to a nonconforming use.
(Ord. 4-62. Passed 3-12-62.)