The following building materials, and none others, shall be allowed in the construction of the exterior walls of buildings and structures constructed and installed in an OP-1 (Office Park 1 District) in the City: the exterior walls of a building or structure shall be constructed of one or more of the following building materials: (a) brick; (b) brick veneer; (c) natural stone; (d) marble; (e) granite; (f) glass; and (g) such other building materials as shall be authorized by the City Council, with the advice and recommendation of the City’s Building Commissioner and the City’s Planning Commission.

The design materials shall be used in such a way as to blend with the scale, color, and traditional architectural character of the district.