The Americans with Disabilities Act (ADA) is a U.S. Federal law that sets the standards for building safe wheelchair ramps for public facilities. The ADA does not enforce wheelchair ramp regulations for private residences, but local building authorities may incorporate the ADA rules into their own guidelines. The ADA regulations ensure that the slope is not too great, that the ramp is wide enough for comfort, that the landings are big enough to safely turn the wheelchair, and that there are handrails and a curb to prevent a wheelchair from falling off the ramp.
Contact your local city or county permit agency to familiarize yourself with any local laws governing wheelchair ramps and the setbacks on your property, including how close to your boundaries a structure may be built.
Draw your plans by hand or with a computer, showing the length, design and slope of the ramp and where it fits in on your lot. A switchback L or U design may be necessary in order to maintain the required slope. According to the ADA requirements as of November 2010, the maximum slope shall be 1:12 for 30 feet -- this means that for every 1 foot rise in elevation the ramp must be 12 feet in length; the maximum rise for any run shall be 30 inches and the minimum clear width (inside the handrails) shall be 36 inches. The ADA also requires that the landing be level, a minimum length of 60 inches clear and at least as wide as the ramp. If the ramp changes direction, the minimum landing shall be 60-inches-by-60-inches.
Add the handrail and curb to your plans per your local or ADA specifications. There must be a handrail on both sides of the ramp, with the top measuring 34 to 38 inches above the floor of the ramp. Handrails should extend 12 inches at the top and bottom where the ramp ends. The ramp must have curbs at least 2-inches high at the sides to prevent anyone from falling off the ramp.
Submit your permit application, which should include your plans showing dimensions and slope, as well as a plan of your lot to show that you will not be violating the setback laws. Most permitting authorities require a list of the materials you plan to use. Pressure-treated wood is a good choice because it won't rot, but you can also use aluminum or concrete.
Build the ramp according to your plans once you receive your permit.