Accessible ramps: slope, landings, handrails

One-line orientation

A slope steeper than 1:20 is a ramp, and 1:12 is the steepest accessible ramp. Ramp rules also govern cross-slope, landings, and handrail extensions.

Key points

• Running slope: 1:12 max (≈8.33%). This is the steepest an accessible ramp may be.
• The 1:20 threshold: a surface at 1:20 or flatter (≤5%) is a walking surface — not a ramp — and does not require ramp handrails. Between 1:20 and 1:12 it is a ramp and must have handrails (once its rise exceeds 6 inches).
• Cross-slope: 1:48 max (≈2%) across the path of travel.
• Landings: level landings at the top and bottom, and one for every 30 inches of rise (and at direction changes).
• Handrails: required on both sides; mounted ~34–38 inches high, with ~12-inch extensions past the ends of the run.
• Other: typical clear width 36–44 inches (sometimes 60” for convenience); 6’-8” minimum headroom; 60” turning space for a wheelchair where the ramp meets a turn (2010 ADA value; 67” under ICC A117.1-2017).

Confusions / comparison

Slope	Classification	Handrails?
≤ 1:20 (≤5%)	Walking surface	No (ramp rules not triggered)
> 1:20 up to 1:12	Ramp	Yes if rise > 6” — both sides + landings
> 1:12	Too steep	Not a compliant accessible ramp

Ramp requirement	Value
Running slope	1:12 max (≈8.33%)
Cross-slope	1:48 max (≈2%)
Landing	Top, bottom, every 30” of rise
Handrail height	~34”–38”
Handrail extension	~12”
Headroom	6’-8” min

Related

→ Accessible routes (this topic): a ramp is part of the route · Reach ranges and transitions (this topic): the small ≤1/2” change-in-level that doesn’t need a ramp · Exit stairs (this module): stair vs ramp as components of egress.