![]() ![]() Handrails As mentioned above, in alterations, stairs between levels that are connected by an accessible route shall not be required to comply with 504, except that handrails complying with 505 shall be provided when the stairs are altered. 2010 ADA Standard 504.7, Wet Conditions, states, “Stair treads and landings subject to wet conditions shall be designed to prevent the accumulation of water.” This is where the allowance for a 1:48 slope on the treads comes in. 2010 ADA Standard 504.6, Handrails, states, “Stairs shall have handrails complying with 505.” See Handrails below. The permitted projection of the nosing shall extend 1½ inches (38 mm) maximum over the tread below.” The graphic above is representative of this Standard. ![]() Risers shall be permitted to slope under the tread at an angle of 30 degrees maximum from vertical. Nosings that project beyond risers shall have the underside of the leading edge curved or beveled. The graphic below is representative of tread nosings.Ģ010 ADA Standard 504.5, Nosings, states, “The radius of curvature at the leading edge of the tread shall be ½ inch (13 mm) maximum. Nosings come in different shapes to include a right angle (90 degrees), an angled nosing that is more than 90 degrees, and a curved or beveled nosing. The leading (front) edge of a staircase step tread/run is referred to as the nosing. Stair landings should meet these same requirements, but again, this is not stated specifically in the 2010 ADA Standards. Stair treads must meet requirements for floor or ground surfaces which specify that the treads and landings need to be mostly flat, surface openings cannot allow passage of a sphere more than ½ inch in diameter, and the surface must be stable, firm and slip resistant. EXCEPTION: Treads shall be permitted to have a slope not steeper than 1:48.” Treads are also sometimes referred to as “runs”. 2010 ADA Standard 504.4, Tread, states, “Stair treads shall comply with 302. Also, some ambulatory disabled individuals who use the steps may use the riser backing to slide their foot up to the level of the next step. This part of the step, sometimes referred to as a riser backing, cannot be open because it could allow a crutch tip or the foot of an ambulatory disabled individual to slip through the opening which could cause a fall. The graphic below is representative of this Standard.Ģ010 ADA Standard 504.3, Open Risers, states, “Open risers are not permitted.” Riser is a reference to the vertical part of the staircase step. ![]() Treads shall be 11 inches (280 mm) deep minimum.” A common measurement is for the riser heights to be within 3/8 inch of each other in height. Risers shall be 4 inches (100 mm) high minimum and 7 inches (180 mm) high maximum. 2010 ADA Standard 504.2, Treads and Risers, states, “All steps on a flight of stairs shall have uniform riser heights and uniform tread depths. State and local building codes may have useful information about staircase landings. Some isolated areas of the Standards mention landings in staircases but specifics regarding length, width, slope, surface conditions are not included. The 2010 ADA Standards do not specifically break out staircase landings. Technical requirements for stairs are covered in 2010 ADA Standard 504.
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