In all Residence Districts, the following obstructions shall be permitted to penetrate a maximum height limit or sky exposure plane. These allowances are generally common to Residence, Commercial and Manufacturing Districts.

1. 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:
   1. shall be limited to a maximum projection from a building wall of 2 feet, 6 inches, except when located on the first story above a setback;
   2. shall have solid surfaces that, in aggregate, cover an area no more than 30 percent of the area of the building wall (as viewed in elevation) from which they project; and
   3. may rise above the permitted building height, up to the height of a parapet wall or guardrail permitted in accordance with this Section. When located on the first story above a setback, awnings and other sun control devices shall be limited to a projection of 50 percent of the depth of the required setback, and shall be limited, in total, to 50 percent of the width of the building wall from which they project;
2. 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 the applicable height and setback regulations;
3. Chimneys or flues, with a total width not exceeding 10 percent of the aggregate width of street walls of a building at any level;
4. Decks, and other surfaces for recreational activities, not more than 3 feet, 6 inches in height, as measured from the maximum height limit;
5. Flagpoles or aerials;
6. Parapet walls, not more than four feet in height, as measured from the maximum height limit. 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;
7. Qualifying exterior wall thickness;
8. Roof thickness, up to 12 inches, to accommodate the addition of insulation, for buildings or portions of buildings constructed prior to December 6, 2023. For a building that has added roof thickness pursuant to this paragraph, the height of any other permitted obstruction may be measured from the finished level of the roof instead of the maximum height limit or sky exposure plane.
9. Skylights, clerestories or other daylighting devices, not more than four feet in height, as measured from the maximum height limit. 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;
10. Solar energy systems, accessory or as part of an energy infrastructure equipment:
    1. on the roof, or any portion thereof, of a building, with a slope less than 20 degrees: up to a height of 15 feet, or, when located on a bulkhead or other obstruction of this Section, a height of six feet; or
    2. on the roof, or any portion thereof, of a building, which has a slope of more than 20 degrees: up to a height of 60 inches in height, as measured perpendicular to the roof surface;
11. Vegetated roofs, not more than 3 feet, 6 inches in height, excluding vegetation, as measured from the maximum height limit. 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;
12. 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;
13. Window washing equipment mounted on a roof;
14. Wire, chain link or other transparent fences.