The outdoor walking and driving areas shall be surfaced with concrete, asphalt, or gravel, or other materials that have been effectively treated to minimize dust, facilitate maintenance, and prevent muddy conditions.
Exterior surfaces of buildings shall be of weather-resistant materials, and shall comply with applicable District laws and regulations.
Outdoor storage areas for refuse, recyclables, or returnables shall be constructed of materials specified in sections 1601 and 1602.
D.C. Mun. Regs. tit. 25, r. 25-B1701