R2A R2X R3 R4 R4-1 R4A R5A

1. In the districts indicated, permitted obstructions are limited to chimneys, qualifying exterior wall thickness, flagpoles or aerials, parapet walls, roof thickness, skylights, solar energy systems and vegetated roofs pursuant to Section 23-621. However, in R3-2 and R4 Districts, except R4-1, R4A and R4B Districts, elevator or stair bulkheads, roof water tanks, energy infrastructure equipment and accessory mechanical equipment shall additionally be permitted.
2. In R2X Districts, dormers may be considered permitted obstructions if:
   1. the aggregate width of dormers facing the street line is equal to not more than 50 percent of the width of the street wall line;
   2. the aggregate width of dormers facing the rear lot line is equal to not more than 50 percent of the width of the rear wall line;
   3. the aggregate width of dormers facing a side lot line is equal to not more than 50 percent of the width of a straight line connecting and perpendicular to the street wall line and the rear wall line; and
   4. on a corner lot, the aggregate width of dormers facing a side lot line is equal to not more than 50 percent of the width of the rear wall line facing such side lot line.

R6 R7 R8 R9 R10

1. In the districts indicated, for Quality Housing buildings, within a required front setback distance above a maximum base height, the following rules shall apply:
   1. Dormers shall be allowed as a permitted obstruction, provided that on any street frontage, the aggregate width of all dormers at the maximum base height does not exceed 60 percent of the width of the street wall of the highest story entirely below the maximum base height. For each foot above the maximum base height, the aggregate width of all dormers shall be decreased by one percent of the street wall width of the highest story entirely below the maximum base height.
      Dormer
      (23-621c, 62-341d.2)
   2. Solar energy systems on a roof shall be limited to four feet or less in height, as measured from the maximum height limit, or the finished level of the roof, whichever is higher. However, on a roof with a slope greater than 20 degrees, such systems shall be limited to 18 inches in height as measured perpendicular to the roof surface.
   3. Wind energy systems shall not be allowed as permitted obstructions.
   4. Window washing equipment shall not be allowed as permitted obstructions.