Unless otherwise authorized in this chapter, all sign frames, supports, and faces
shall be steel, wood, aluminum, or masonry construction as provided for in the functional
standards table, contained in section 32-366. All signs constructed of wood, when authorized by the provisions of this chapter,
shall be constructed of decay-resistant materials. Plastic inserts shall be allowed
on illuminated signs, when illumination is provided from within the sign. Raised plastic
letters shall be allowed as sign face material when affixed directly to a wall surface.