For a building wall facing a narrow street, at least 25 percent of the total surface area of such building wall up to a height of 12 feet above curb level or to the ceiling of the ground floor, whichever is higher, shall be transparent. Transparent areas may include storefronts subject to Section 109-50 (SPECIAL REVIEW PROVISIONS). Door or window openings within such surface areas shall be considered transparent. Such openings shall have a minimum width of two feet.
In addition, any portion of such building wall 20 feet or more in length, which contains no transparent area at ground floor level, shall be covered with vines or similar planting in permitted front wall recesses, or be treated so as to provide visual relief from large expanses of blank walls. Planting shall consist of shrubs, ivy or creepers and shall be planted in soil having a depth of not less than 2 feet, 6 inches, and a minimum width of 24 inches.