23-62 Permitted Obstructions

(a)        Awnings and other sun control devices, provided that when located at a level higher than the first story, excluding a basement, all such awnings and other sun control devices:

(b)        Balconies, unenclosed, subject to the provisions of Section 23-13;

(c)        Building columns, having an aggregate width equal to not more than 20 percent of the aggregate width of street walls of a building, to a depth not exceeding 12 inches, in an initial setback distance, optional front open area, or any other required setback distance or open area set forth in Sections 23-63, 23-64, 23-65 (Tower Regulations) or 23-66;

(d)        Chimneys or flues, with a total width not exceeding 10 percent of the aggregate width of street walls of a building at any level;

(e)        Decks, and other surfaces for recreational activities, not more than 3 feet, 6 inches in height, as measured from the maximum height limit, or the finished level of the roof as it existed on April 30, 2012, whichever is higher;

(f)        Dormers having an aggregate width of street walls equal to not more than 50 percent of the width of the street wall of a detached or semi-detached single- or two-family residence ;

(g)        Elevator or stair bulkheads (including shafts; and vestibules not larger than 60 square feet in area providing access to a roof), roof water tanks and accessory mechanical equipment (including enclosures), other than solar or wind energy systems, provided that:

(h)        Exterior wall thickness, up to eight inches, where such wall thickness is added to the exterior face of a building wall existing on April 30, 2012, provided the added wall thickness has a thermal resistance (R-value) of at least 1.5 per inch. Where buildings that have added exterior wall thickness pursuant to this Section are enlarged, such enlarged portion may similarly penetrate a maximum height limit in order to align with the exterior walls of the existing building, provided such enlargement contains less floor area than the existing building, and there is no penetration of floor area above a maximum height limit;

(i)        Flagpoles or aerials;

(j)        Parapet walls, not more than four feet in height, as measured from the maximum height limit, or the finished level of the roof as it existed on April 30, 2012, whichever is higher. A guardrail with a surface at least 70 percent open or with an opacity no more than 30 percent (as viewed in elevation), shall be permitted above a parapet wall or within two feet of a parapet wall, provided such guardrail is not more than four feet above the accessible level of a roof. Such restriction on guardrail height shall not apply when located beyond two feet from a parapet wall;

(k)        Roof thickness, up to eight inches, to accommodate the addition of insulation, for buildings or portions of buildings constructed prior to April 30, 2012. For a building that has added roof thickness pursuant to this paragraph, an enlargement may align with the finished roof surface of such building, provided the enlarged portion does not exceed the maximum height limit by more than eight inches;

(l)        Skylights, clerestories or other daylighting devices, not more than four feet in height, as measured from the maximum height limit, or the finished level of the roof as it existed on April 30, 2012, whichever is higher. Such devices shall be limited to a lot coverage not greater than 10 percent of the lot coverage of the roof and be located at least eight feet from the street wall edge. However, such devices shall not be permitted obstructions above a roof with a slope greater than 20 degrees;

(m)        Solar energy systems:

(n)        Vegetated roofs, not more than 3 feet, 6 inches in height, excluding vegetation, as measured from the maximum height limit, or the finished level of the roof as it existed on April 30, 2012, whichever is higher. On roofs with slopes greater than 20 degrees, vegetated roofs shall be limited to a height of 12 inches measured perpendicular to such roof surface;

(o)        Weirs, check dams and other equipment for stormwater management, not more than 3 feet, 6 inches in height, as measured from the maximum height limit, or the finished level of the roof as it existed on April 30, 2012, whichever is higher;

(p)        Wind energy systems on portions of buildings with a height of 100 feet or greater, provided:

(q)        Window washing equipment mounted on a roof;

(a)        In the districts indicated, permitted obstructions are limited to chimneys, exterior wall thickness, flag poles or aerials, parapet walls, roof thickness, skylights, solar energy systems and vegetated roofs pursuant to Section 23-62. However, in R3-2 and R4 Districts, except R4-1, R4A and R4B Districts, elevator or stair bulkheads, roof water tanks and accessory mechanical equipment provided pursuant to paragraph (g) of Section 23-62 shall be permitted for buildings containing affordable independent residences for seniors.

(b)        In R2X Districts, dormers may be considered permitted obstructions if:

(c)        In the districts indicated, for Quality Housing buildings, the permitted obstructions set forth in Section 23-62 shall apply to any building or other structure, except that within a required front setback distance above a maximum base height, the following rules shall apply: