The walking surface of treads and landings of stairways shall be sloped not steeper than one unit vertical in 48 units horizontal (2-percent slope) PHOTO 28.
Exception: Where the surface of a landing is required elsewhere in the code to drain surface water, the walking surface of the landing shall be sloped not steeper than 1 unit vertical in 20 units horizontal (5-percent slope) in the direction of travel.

