A ramp's rise ratio should not exceed 1:12; that is, a ramp can only rise 1 inch per every 12 inches of length under the Americans with Disabilities Act, indicates AmRamp. Ramps longer than 6 inches must have handrails. An intermediate platform must break up any ramp that is longer than 30 feet.
There must be side flanges of 2 inches or more to prevent slippage off the ramp, notes AmRamp. Ramps must also have non-skid surfaces for safety, and they must be constructed in such a way that they prevent water from accumulating in any spot. Builders should consult with their contractors to ensure their ramps meet all regulations.
The Americans with Disabilities Act sets standards for wheelchair ramps in new facilities built or major renovations undertaken of public places after 1991, according to Amramp. Such standards mandate the rise ratio, when guard rails are required, the surface material of ramps, the size of side flanges and other details.
The types of public places that the ADA covers include government buildings, polling locations, offices, apartment complexes, restaurants and stores, says Amramp. The regulations do not apply to private residences or such places built or renovated before the ADA took effect.