There are a number of factors to consider when deciding on a ramp system.
Before you get too far, you need to decide if a ramp is actually the best available option!
Step #1: Determine the best access point:
Make sure that the doorway you want to use is wide enough to accommodate a wheelchair. Also look at the interior arrangement just inside that door and the path inside the building after entering. Make sure that there is a clear space to approach the door.
Which Side of the Building is Best?
Will a ramp facing the street reduce your home's "curb appeal"?
Will the ramp interfere with other uses of the property?
Avoid areas under trees that might drop excessive leaves on the walking surface.
Try to get southern exposure to aid in drying and melting of snow and ice from the walking surface.
Step #2: Measure the rise:
Measure the rise from the door threshold or from the landing outside the door to the flat area that the other end of the ramp will rest on. Keep in mind that the ground may slope away from the bottom of the steps. (see diagram)
NOTE: If the measured rise is greater than 30", it might be more cost effective to consider a motorized lift instead of a ramp system.
If the rise is less than 6 inches, or the need for a ramp is temporary, it may be best to use a portable ramp.
Step #3: Determine the Best Layout:
Straight In - This is best of you have room for the entire length of the ramp to project straight out from the entrance. (see diagram)
L-Shape - If you don't want the ramp projecting straight out of the entrance, or if your desired landing area is on a different side of the building, you can "wrap" the ramp around a corner. (see diagram)
Switch Back - This is best if you want to minimize the total amount of space that the system takes up on your property. (see diagram)
Addition of Stairs - If you decide to use the primary building entrance for your ramp system, consider the other people that will be using this entrance. Do you want to force them to walk up the ramp? If not, think about providing steps that go directly from ground level to the top of the highest platform of the ramp system.