Need Help Designing a Wheelchair Ramp

I think an ADA requiremnet is a ratio of 1:20, your ratio mentioned above is for a ramp ratio of 1:12. A picture of the stairs might be a good idea. If the steps are concrete use some tapcon screws to fastern the wood to the steps. Has far the hand rail goes you can make a curb along the edge of the ramp. When I’v done wheelchair ramps I like to frame them so that I can deck the ramp with longer boards running lentghwise up & down the ramp and not side to side. You’ll better drainage and the ramp will last longer and it is easier to roll up and down the ramp. Dealing with a carport you may have to make a midlanding and do the switchback thing.

-- Darrell, making more sawdust than I know what to do with

Thanks, devann. We were planning to use three stretchers (10” O.C.), and 3/4” exterior plywood for the decking. This seems to meet the code. What size decking boards do you use, and how do you support them?

-- Jim in Tennessee

We did a website for www.TexasRamps.org. They may be able to help you.

-- You can't control the wind, but you can trim your sails

Some how I double posted see below

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/

I use 2-2×8s for the beams (sides) of the ramp then 2×6s for joist and decking. I connect the joist to the beams with joisthangers, then deck. If you’re going to use plywood you may want to use some boatdeck paint to cover it. Or use some of that stick on sandpaper stuff used for stair treads.

-- Darrell, making more sawdust than I know what to do with

You need one foot of length for every inch of height(or rise) so if the high part of the ramp is 14” off the ground it needs to be 14ft long. I’ve built many ramps over stairs . Many times the stringers have to have notches over the first or second stair. In my are ramps need hand or safety rails on both sides unless one side is against a wall. Hand rails can not have spaces larger then 4” wide. Also the bottom part of the ramp needs to be connected to the ground.
Depending on the length of the stringers(2×8 or larger) you may want to put one or two sets of post down to the ground cemented in to prevent bounce.

-- W James Brokenbourgh Custom furniture maker http://artisticwoodstudio.com/

ADA is 12 to 1 or 8% grade or 1” per ft. however you want to say it. I know there’s a min flat platform on any turns and at the top by the door. Min width is 42” on the ramps. And most definitely need railings. I’ve done plenty commercial buildings that way. And I don’t believe the ADA rules would be any different for residential…but maybe.

-- New Auburn,WI

A4.8.2 Slope and Rise. Ramp slopes between 1:16 and 1:20 are preferred. The ability to manage an incline is related to both its slope and its length. Wheelchair users with disabilities affecting their arms or with low stamina have serious difficulty using inclines. Most ambulatory people and most people who use wheelchairs can manage a slope of 1:16. Many people cannot manage a slope of 1:12 for 30 ft (9 m).

I copied this from the ADA website. I to have done a few commercial jobs and the guy with the pen darwing the plans always ask for the 1:20 ratio. The 1:12 ratio is a max allowed incline.

www.access-board.gov/adaag/html/adaag.htm

-- Darrell, making more sawdust than I know what to do with

I have never designed a wheel chair ramp. I spent a few years confined to a wheelchair and someone else built my ramp for me. Being someone who has had to use a ramp at home though, there is one thing I have to plead with you to do. Be sure to put adhesive backed non-skid strips across the ramp at no more than six inches apart all the way up the ramp. If the person in the wheelchair needs to get down it in the rain, even a not so steep ramp can be plenty slippery enough to send a wheel chair sliding out of control, causing severe injury. I know this all to well from experience. Please apply non-skid strips.

-- http://wddsrfinewoodworks.blogspot.com/

Devann, you said: “If you’re going to use plywood you may want to use some boatdeck paint to cover it. Or use some of that stick on sandpaper stuff used for stair treads.”

William, you said: “Be sure to put adhesive backed non-skid strips across the ramp at no more than six inches apart all the way up the ramp.”

Good advice, and I thank you both for it! Now I have a followup question: Has anyone ever mixed fine sand w/ paint (in this case, “boatdeck” or some other weatherproof paint) to achieve a high-friction surface on the plywood? Can this take the place of the non-skid strips?

-- Jim in Tennessee

Jim, I made a ramp for a bar so they could use a dolly (two wheeler) to get their ice and tried the sand in the paint trick. It didn’t work out. I was constantly repainting until a bought the boat deck paint. Sometimes I have to learn the hard way. A friend has the stick on strips on his pressure treated steps and it has been holding up pretty well. Not sure how good they’ll work on a painted surface.

-- Darrell, making more sawdust than I know what to do with

The problem with the paint in the sand thing is that the paint isn’t strong enough to hold the sand under stress. If you want to go this route, one option that I’ve heard of is using truck bed liner material. It is sold as spray on or brush on and has some special compound that help it take abuse.

-- http://wddsrfinewoodworks.blogspot.com/

The 1’ per inch is correct, as well as having hand rails. Be sure that there is a 4” rail along the bottom of the hand rail for the wheel stop. The minimum width of the ramp is 36” and if you have any turns in the ramp you need a 5’x5’ landing or pad.

The one I built for Mom was over 2 steps. I had to attach a nailer to the concrete porch to build from. It was 48” wide and 10’ to the turn landing then the 5’x5’ turn landing and then a 6’ extension to the drive. The handrails were 36” high. I used all pressure treated lumber. After it was built I let it dry for 2 months and then I primed and painted it with flat paint. I then took spray on under coating for automobiles and sprayed the walk way of the ramp and landing. This provided a surface that was skid free and has held up well.

-- I don't make mistakes, I have great learning lessons, Greg