The Board may authorize issuance of a zoning certificate, after public hearing, for the following:
(a) The substitution for nonconforming uses of another nonconforming use, if no structural alterations, except those required by law or regulations, are made, provided that in any R District no change shall be permitted to any use prohibited in a B District, and in any B District no change shall be permitted to any use prohibited in any M District.
(b) The extensions or completion of a building or land use devoted to a nonconforming use upon a lot occupied by such building or land use, or on a lot adjoining, provided that such lot was under the same ownership as the lot in question on the date such building or land use became nonconforming, and where such extension is necessary and incidental to the existing use of such building or land use, provided that the floor area of any extension shall not exceed, in all, thirty-five percent of the floor area of the existing building or buildings devoted to a nonconforming use and provided further, that such extension or extensions shall be undertaken within five years of the date when the use of such building became nonconforming.
(c) The extension of a nonconforming use throughout those parts of a building which were manifestly designed or arranged for such use prior to the effective date of this Zoning Ordinance (Ordinance 11-71, passed May 25, 1971), if no structural alterations, except those required by law, are made therein.
(Ord. 11-71. Passed 5-25-71.)