A paved surface should be sloped for drainage at about what minimum cross slope?

Giải thích

Paved surfaces such as patios and walkways are typically sloped about 1 to 2 percent, roughly 1/8 to 1/4 inch per foot, to shed water without being noticeably tilted. A dead-level surface ponds water, while too steep a slope is uncomfortable and unsafe. Water should always be directed away from structures.