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City of San Mateo Municipal Code.


(a) A nonconforming building may be enlarged or extended only if the entire building is thereafter devoted to a conforming use, and is made to conform to all the regulations of the district in which it is located.

(b) No building partially occupied by a nonconforming use shall be altered in such a way as to permit the enlargement or expansion of the space occupied by such nonconforming use.

(c) No nonconforming use may be enlarged or extended in such a way as to occupy any required usable open space, or any land beyond the boundaries of the zoning plot as it existed at the effective date of this title, or to displace any conforming use in the same building or on the same parcel.

(d) A building or structure which is nonconforming with respect to yards, floor area ratio, or any other element of bulk regulated by this title may be altered to expand the interior floor area but shall not increase the degree or extent of its nonconformity with respect to the bulk regulations for the district in which it is located.