How to Convert Steps to Wheelchair Access Ramp

Construct the top landing at the top of the stairs. If the landing is at a doorway, it should be no more than 1/2 inch lower than the door sill. The landing should provide at least 2 feet of space to the side of the door latch so the door can be opened by the wheelchair user independently. For most entrances, a 58 x 58-inch landing will suffice. Use wood decking to construct the landing, which can usually be laid out over the existing top landing. If you need to go beyond this area, use 4 x 4-inch posts for additional support, and attach the decking to the posts with bolts. Attach the pieces of decking together using bolts.

Add an additional piece of decking flush to the rise of the top stair with 4 x 4-inch posts on either side. This will be where you screw in the sloping part of the ramp.

Determine the length of the ramp by using the Americans with Disabilities Act (ADA) guideline of 1:12. This means for every 1 foot of rise (change in elevation), you will need 12 feet of run (change in length). The slope can be more gradual if desired. Once the length is determined, you can design a layout for the ramp. If you have ample room, your ramp may go straight out from the door. If not, consider an L-shaped or U-shaped ramp. Allow for landings every 30 feet. Any 90-degree turns will need a 58 x 58-inch landing. Any 180-degree turns will require a 58 x 92 1/2-inch landing. Allow ample width for the wheelchair -- between 39 and 42 inches. This layout will be used to construct the base and frame for the ramp.

Construct the base for the ramp with 1 x 6-foot runners, using stakes and a rubber mallet to secure the runners firmly in the ground. The runners should follow the layout you have designed for the ramp. The end runners should be flush with the ground.

Install the 4 x 4-inch posts every 5 feet along the ramp, securing them to the plywood bearing plates with bolts and screws. Use screws to attach plywood gussets to the posts in order to reinforce the ramp and promote a gradual slope. The bearing plates will need to be secured to the runners with screws.

Construct the frame of the ramp using the 2 x 6-foot boards. The frame will fit over the runners, so use these as a guide. Attach the frame to the 4 x 4-inch posts using screws every 5 feet. Include a joint every 10 feet by laying a 2 x 6-foot piece of lumber across the frame and fastening it with screws. Car jacks may be used to temporarily hold the materials in place while you determine the accuracy of the slope using a level.

Top the frame of the ramp with treated wood decking, securing the decking with screws along the way. Attach at least 1 inch of additional decking along the bottom sides of the ramp to prevent slipping. Handrails must also be constructed along both sides of the ramp in order to comply with building standards, which will vary depending on your location. The handrails can be constructed using any additional lumber from the completed project.