How To Calculate The Total Length Of The Ada Ramp And Platforms
To determine the length of the ramp, first, you need to determine how high the ramp rises vertically (in inches) to the threshold, which is the distance from the floor to the floor of the door you’re trying to get to. Once you’ve determined that the height of the ramp is vertical, you will be able to add that number to your ADA slope calculator.
Be aware that calculations are done on the assumption that ground conditions are level. If the ground isn’t level, you must learn to maintain a stable slope when you have uneven terrain.
ADA Ramp Slope
An ADA ramp slope should be not steeper than 1:22 (1-inch vertical rise up to 12 inches in length of the ramp.) According to ADA, this requirement must be met for every ramp for wheelchairs that is utilized by the general public.
As an example, let’s say there is a vertical rise of 10″. To determine the ramp’s ADA-required length, simply multiply that height of the vertical rise (10″) by 12”. Once you’ve calculated the length of the ramp it is a lot easier to round up to the nearest foot. This is done to make it easier for reasons of planning.
ADA Ramp Landing Requirements
This is where it gets complicated when it comes to calculating the entire distance of the ramp.
The ADA requires that there be a second resting platform for each additional 30 inches of length. If the ramp is able to change direction towards the platform the platform has to measure 60” by 60 inches. When the ramp has a straight line, it is required that the platform has to be at a minimum as wide as the ramp. It should be at least 60 inches long.
When you have calculated the necessary ADA ramp length by using the ADA ramp slope equation. Consult this table to determine the number of platforms you are required to include. Each platform adds sixty” to the total distance of your ramp.
The ADA also stipulates that there should be a 5’x five-foot clearing at the bottom and top of the ramp so that wheelchair users are able to sit. In general, it is not necessary to buy a platform for the bottom of the ramp as it is situated on a walkway or parking space with plenty of space. If you don’t have an area or platform on the upper part of the ramp you’ll have to buy an additional platform that will add 60 inches to the total length of the ADA ramp will cover.
Example: ADA Ramp and Platform Project
Here’s a project sample that we’ll walk through to determine the total distance of ADA ramps and platforms.
The facts:
- I am the administrator of a school that requires an accessible ramp.
- The door is located off the ground and there is no platform or staircase that leads to the door.
- The ground is nearly flat, but when I walk further away from my door, in the direction the ramp will be the ground starts to slope upwards.
The calculation:
- I’m measuring the vertical rise of the floor to the top of the door. it is 49.75″.
- To determine the distance of the ramp, at the 1:12 required ADA ramp slope I multiply 49.75″ by 12, which is 597″‘ (49.75’).
- After taking measurements of how steep the soil slopes I find that I will need just 575” (47.9′) to keep that 1:12 slope. I’ll round to the nearest full feet (48′) to simplify the calculations.
- Then I’ll take a look at the required platforms table below. My ramp meets the specifications for the 2nd row. Therefore, I’ll need to add (1) 60″x 60″ platform that splits along all the way down the ramp.
- I also require (1) 60″x 60″ to the highest point of the ramp.
- Choose your ADA ramp configuration that is suitable for your needs. If you decide to go with the switchback ramp you’ll need a minimum (1) additional platform. In this case, we will choose an L-ramp, so that it doesn’t block the existing tree.
- The total length of the ramp measures 696 (58′) long. (58′) long.
