D.C. Mun. Regs. tit. 24, r. 24-312
No portion of a sidewalk cafe, including, but not limited to, doors, windows, walls, or any other objects designed as part of a sidewalk cafe or placed within a sidewalk cafe, shall swing or project beyond the designated exterior perimeter of the sidewalk cafe; Provided, that this provision shall not apply to fire exit doors which are used exclusively as emergency fire exit doors.
All furnishings of the sidewalk cafe including, but not limited to, tables, chairs, and decorative accessories, shall be readily moveable.
The fixtures of a sidewalk cafe shall not be bolted or permanently affixed to public space, except that screw sockets may be permitted as a form of anchoring when approved by the Public Space Committee.
Any object to be affixed or attached to a wall or ceiling of a sidewalk shall be shown on the plan and approved by the Public Space Committee.
The floor of a sidewalk cafe shall be at the same elevation as the existing surface space, except as provided in § 312.6.
In order for the floor of the sidewalk cafe to be at level grade, the floor of the sidewalk cafe may be constructed so as not to exceed eighteen inches (18 in.) above the sidewalk where the sidewalk cafe meets with the adjoining clear sidewalk space.
D.C. Mun. Regs. tit. 24, r. 24-312