ADA ramp requirements: slope, rise, landings and handrails

When the ADA ramp rules apply

Section 405.1 is short: ramps on an accessible route must comply with §405. So the question is whether your ramp is part of an accessible route. Under the 2010 ADA Standards, newly constructed or altered state and local government facilities (Title II) and places of public accommodation and commercial facilities (Title III) must provide accessible routes. A ramp on one of those routes must meet §405.

Private single-family homes are generally not covered by ADA Title III, so §405 is not legally binding there — but it is the most widely used reference for a safe, usable residential ramp, and local residential codes such as the IRC apply instead (seepermits and local rules).

Requirements at a glance

Running slope (§405.2)

Ramp runs must have a running slope not steeper than 1:12 — 1 inch of rise for every 12 inches of run, which is 8.33%. A gentler slope is always allowed and is easier to use, especially for manual wheelchairs: 1:16 (6.25%) and 1:20 (5%) are common choices where space allows.

A slope of 1:20 or flatter is not a ramp under the ADA at all — the Standards define a ramp as "a walking surface that has a running slope steeper than 1:20" (§106), and such surfaces are covered by the walking-surface rules in §403 instead.

For existing sites, buildings and facilities only, Table 405.2 permits steeper slopes where space limits make them necessary, with a reduced maximum rise:

The exception is for existing conditions, not a shortcut for new construction. If you can fit 1:12, use it.

Cross slope (§405.3)

The cross slope — the side-to-side tilt across the ramp — must not be steeper than1:48 (2.08%). Cross slope matters more than people expect: it steers a wheelchair toward the downhill edge and makes the ramp harder to control. Build it as flat as drainage allows.

Surfaces (§405.4)

Ramp run surfaces must comply with §302: stable, firm and slip resistant(§302.1). Changes in level other than the running slope and cross slope are not permitted on a ramp run. For surfaces with openings — decking boards, grates — openings must not allow a ½ inch (13 mm) sphere to pass, and elongated openings must run perpendicular to the direction of travel (§302.3).

Clear width (§405.5)

The clear width of a ramp run must be 36 inches (915 mm) minimum. If handrails are provided, the clear width between them must also be at least 36 inches — handrails cannot eat into the required width.

Rise per run (§405.6)

No ramp run may rise more than 30 inches (760 mm). Longer climbs are built as a series of runs with landings between them, which also gives wheelchair users and anyone walking a place to stop and rest. This is why a 35 inch rise becomes two runs of 17.5 inches, and a 60 inch rise becomes two runs of 30 inches.

Landings (§405.7)

• A landing is required at the top and bottom of every ramp run (§405.7).
• Clear length at least 60 inches (1525 mm) (§405.7.3).
• Clear width at least as wide as the widest run leading to the landing (§405.7.2).
• Where the ramp changes direction between runs, the landing must be at least60 × 60 inches (§405.7.4) so a wheelchair can turn.
• Landings must comply with §302: no changes in level, and slopes no steeper than 1:48 (§405.7.1).
• Door maneuvering clearances may overlap the landing area where a door is adjacent (§405.7.5).
• Landings in wet conditions must be designed to prevent water accumulation (§405.10).

Because every run has a landing at each end, a ramp with N runs has N + 1 landings: one run means two landings; two runs mean three (top, middle and bottom).

Handrails (§405.8, §505)

Ramp runs with a rise greater than 6 inches (150 mm) must have handrails complying with §505 (§405.8). Handrails are required on both sidesof ramps (§505.2, with a narrow exception for aisle ramps in assembly areas).

• Top of the gripping surface 34–38 inches (865–965 mm) above the ramp surface, at a consistent height (§505.4).
• Continuous within the full length of each run (§505.3).
• Gripping surfaces must not rotate in their fittings, and must be free of sharp or abrasive elements (§505.8, §505.9).
• Circular handrails: 1¼–2 inches outside diameter (§505.7.1).
• At least 1½ inches (38 mm) clearance between the handrail and adjacent surfaces (§505.5).
• Gripping surfaces extend at least 12 inches (305 mm) beyond the top and bottom of each run (§505.10.1).

Edge protection (§405.9)

Edge protection is required on each side of ramp runs and landings — it keeps wheelchair casters and crutch tips from slipping off the edge. It can be either:

• Extended surface (§405.9.1): the ramp or landing surface extends at least 12 inches (305 mm) beyond the inside face of the handrail; or
• Curb or barrier (§405.9.2): a curb or barrier that prevents a 4 inch (100 mm) diameter sphere from passing anywhere within 4 inches of the surface.

There are limited exceptions, for example where a ramp does not require handrails and has flared sides, and on some landing sides serving an adjoining run or stairway.

Wet conditions (§405.10)

Landings subject to wet conditions must be designed to prevent the accumulation of water. In practice that means a slight drainage slope (within the 1:48 maximum) toward a safe discharge, and no ponding where the ramp meets the landing.

How to measure rise

The rise is the total vertical distance the ramp must climb, measured from the lower surface to the top landing surface — not the number of steps and not the diagonal length of the slope.

1. Identify the two finished surfaces: the ground or walkway at the bottom, and the porch, deck or door threshold at the top.
2. Measure vertically between them at the actual ramp location. A level and a tape measure, or a straight edge with a string line, both work.
3. If you are working from steps, multiply the number of risers by the actual riser height. Risers vary: the IRC caps residential riser height at 7¾ inches (R311.7.5.1), so 12 steps is roughly 84–93 inches of rise — measure rather than assume.
4. Enter the rise in the ramp calculator in inches or centimeters to get the plan.

Common rises and ramp lengths

At the ADA maximum of 1:12, the ramp run is 12 times the rise. This table shows the plan the calculator produces for common rises:

The 84 in row is the rough rise of 12 typical 7 inch steps. Runs are split evenly, and every run keeps its rise at or under 30 inches (§405.6).

Typical materials

The ADA sets performance requirements — stable, firm, slip resistant (§302.1) — not materials. Any of the common options can comply if built and maintained well:

• Concrete: durable and low-maintenance, with a broom or brushed finish for slip resistance. Needs formwork, curing time and proper drainage detailing.
• Pressure-treated timber and decking: common for residential ramps. Board gaps must not let a ½ inch sphere pass (§302.3), and timber needs periodic sealing and inspection.
• Aluminium modular ramps: fast to install and adjustable, often rented for short-term needs. Check the manufacturer's load rating and the surface finish, and make sure the installed slope, landings and handrails still meet the numbers above.
• Composite decking: low maintenance and consistent texture; spans and expansion vary by product, so follow the manufacturer's framing requirements.
• Pavers or stone: firm and stable when properly bedded; joints must stay tight and the surface even.

Whichever you choose, plan for drainage (see §405.10) and keep the surface clear of loose gravel, moss and ice.

Permits, codes and local rules

A permanent ramp is usually a structure, so most jurisdictions require a building permit and an inspection. The ADA is a federal civil rights law; it is enforced separately from building codes, and state or local codes can be stricter than the federal minimum. Before you build, check with your local building department, and if you rent or own under an HOA, check those rules too.

For residential projects, the International Residential Code (IRC) provides the usual baseline. In the 2021 IRC, Section R311.8 covers ramps (later editions renumber this chapter — check your adopted edition):

• R311.8.1 — ramps serving the required egress door: slope not more than 1:12 (8.3%); other ramps: maximum 1:8 (12.5%), with a 1:8 limit where site constraints make 1:12 technically infeasible.
• R311.8.2 — landings at the top and bottom of each ramp, where doors open onto ramps, and where ramps change direction: at least 36 inches (914 mm) deep and no narrower than the ramp.
• R311.8.3 — handrails on at least one side of ramps steeper than 1:12, 34–38 inches high, continuous, with a 1½ inch gap to walls.

The IRC is adopted state by state with local amendments, so always confirm the edition and wording with your local code authority.