I have to build a wheel chair ramp from a garage floor into a house and it is about a 4 foot drop from the doorway to the garage floor. I need to figure the exact angle for the distance I have to work with so I can be sure and cut the ends of the main 2 x 6 supports at an angle that will lay flush against the floor. Does anybody know a formula that would tell me the angle that would come from a certain height going out a certain distance?
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Replies
(rise/run) x (tan*-1)
or
(rise/run) x (inverse tan)
ADA compliant wheelchair ramps should not exceed a 1" rise per 1' run.
Edited 5/24/2007 12:25 pm ET by McMarky
You obviously know what you’re talking about but math involving formulas was never my strong suit. Are you saying I should multiply the height of the doorway by the distance of the ramp to get the angle?
That's not what he's saying. The angle is a trigonometric function of run and rise. Your rise is 4'. You didn't specify the run -- that's the horizontal distance from a point on the ground plumb from the top of the ramp to the point on the ground where the ramp ends. If you are weak on trig, you might consider simply using a carpenter's square to generate the angle on your board. If your rise is 4' and your run is 12', that's a 4/12 slope. (4 inches rise for every 12 inches of run.) Put the 12" mark of the square on the edge of the board, and tip it so the 4" mark hits the edge as well. That's the angle. You can pick up a booklet that shows how to do this, and other wonderous deeds using a square, pretty much anyplace that sells squares.
Mike HennessyPittsburgh, PA
I have the exact measurements for the ramp I need to build. Now keep in mind this is in a private home for a relative and restrictions, code etc. have nothing to do with the project. The height of the ramp is 34 inches. The length is 15 feet. The length can vary a few inches either way if it will give me an even angle. Can you help me figure the angle so the 2 x 6’s will be flush against the garage floor? Again, I’m not interested in any restrictions on ramps. This is the distance I have to work with and my relative is fine with the project.
let's round your 34 in. rise to 3 ft.
so, it's 3ft. rise and 15ft run.grab your handy framing square and line up 3 on the short leg of the square and the 15 on the long leg. make sure you use the same edge of the square (inside or out - not both) scribe both sides. the line on the '3' side is the angle where the ramp meets the house and the other is ramp to floorsee!? no angle needed if you look at it as a ratio. 3:15 =1:5sounds steep to me, but that how you get the cut linepeace
yes it will be steep but it's all the area I have to work with. Thanks for your help.
If you have an area 15 feet from the door, why not build a 30 ft long ramp rising 17 inches, and turning back to the door and rising another 17 inches over the next 15 feet? I's still try to buy another 4 feet (2 ft each way) and maintain a 1:12 slope.
I know you need a flat at the turnaround, but get the concept of attempting to meet the 1:12 spec as close as possible.
For 1:5, the operator better have very strong arms and hands.
GREG
<!---->•••••••
Exo 35:30-35<!---->
The user of the ramp will not be using it except with the help of others.
The reason for the codes is not to be a pain for people to implement. They are there for a reason. Especially those pertaining to the ADA and folks who are wheelchair bound.You are doing your relative a disservice by purposefully making a ramp too steep. As another poster pointed out. Maybe you should consider a lift.Safety should be the utmost concern. Either figure out how to build the ramp properly, or find some other alternative.JP
JP,
Or a rocket-assist jetpack for the rear of the chair, yeah, that'd work, arrrhh arrrh arrrrhhh, more power!
Sincerely,
Tim (the tool man) Taylor
Something like this?http://www.engadget.com/2004/08/30/the-jet-powered-wheelchair/J.P.
JP
Well, that'd get a fellow down a ramp ok, but to go up, I reckon you'd need...more power.
Ray
I have the exact measurements for the ramp I need to build. Now keep in mind this is in a private home for a relative and restrictions, code etc. have nothing to do with the project.
_________________If one of your relative's guests is injured using a ramp you built that's not to code, I would suspect that a court would hold you liable.Additionally, if a building inspector happens upon it, you'll be stuck with (1) building without a permit and (2) not complying with code.Might want to consider that.Leon
My hazy trivia-neglectful mind says the slope of a wheelchair ramp is 1:12. Assuming this is accurate, the angle would be 4.76º. This is difficult to mark out accurately. So, the way to do it is simply mark it directly onto your board. Use a convenient reduction scale to mark a line at the 1:12 slope. That is your cutline.
This is true no matter how many switchbacks and landings you place in the total run. Because the slope must always be the same.
Here are some guidelines for ramp slope.
1:12 is the maximum.
http://www.mobility-advisor.com/wheelchair-ramp-specs.html
In case the meaning of the 1 in 12 requirement hasn't registered, your 4 foot drop will require a 48 foot long ramp to meet the guidelines.
John W.
If you can ascertain that a motorized chair is to be used you may not have to comply with the 1 to 12 requirement, and that requirement may not apply anyway in a private home.
Obviously if the individual is extremely infirm, and a motorized chair will not be used, then you'll have to be even more conservative with the slope of the ramp.
I'm not sure, so please research carefully.
Personally, I would tear out a wooden ramp when the house is being prepared for sale. You don't need the legal headaches. Anyway, it will have served its purpose.
Please read this disclaimer which is an integral part of my post: Do not copy, print, or use my posts without my express written consent. My posts are not based on fact. My posts are merely my written opinions, fiction, or satire none of which are based on fact unless I expressly state in writing that a statement is a fact by use of the word "fact." No one was intended to be harmed in the making of this post.
Edited 5/24/2007 4:02 pm by ThePosterFormerlyKnownAs
If you are building this ramp for yourself or your family, then have at it.
But if you are doing this for someone else you'll need to consider building codes and ADA guidelines. Others have already mentioned the 1:12 guideline, and the fact that there can be reasons that even that isn't gentle enough.
The thing you REALLY need to determine it this: If the steepness of your ramp could be construed (say, ten years from now) to have been the cause of an injury, what is your liability. And even more important - are you covered for that liability? If it's built to code, you probably won't be liable. If not, you will be.
And that is yet one more reason that we should be following codes and guidelines whenever they exist.
Support our Troops. Bring them home. Now. And pray that at least some of the buildings in the green zone have flat roofs, with a stairway.
you guys, and girls are making this way to hard for most to follow. It seems to me that if this is for home and/or a family member anything close to code will help this dis-abled person and I'm quite certain that they will be quite grateful for having a new ramp that will make it easier and safer than what they have now. If commercial, follow ADA guidlines as you certainly have the potential to be held liable not only by the client but also by any person and/or persons. Hope the ramp helps, as the dis-abled need all the help they can get!
Without getting into the law, here is how you calculate the angle you want.
Put this formula into Excel:
=DEGREES(ATAN(h/l))
h = height (4 feet in your case) and l = length. Substitute the actual numbers for h and l, and make sure you use the same units (in other words, don't use feet for the height and inches for the length).
The ADA sets the slope for wheelchair ramps at 1:12, as said before. If necessary, switchbacks will take care of the max length of 48'.
In addition to the 1" per foot rise, you also need to know that the maximum rise for a single ramp is 30". If you have to go up 4', then you need 2 ramps with a 5'x5' landing between them.
Ok...continuing on about the length of the ramp if you kept to code: with the 5' landing now you're up to a 53 foot ramp. Don't know about your garage but that wouldn't work with mine even with switchbacks. Have you considered ditching the ramp idea in favor of a wheelchair lift?
The others are of course correct in the 1:12 etc... I think what you are doning is good and they will be greatfull. Its not perect, its not code, but it is better then the alternative. God bless Reading this post was up lifting and depressing as well, seems the point of this man is helping another was lost and a nasty tone came threw... it may be me. its late here.
Take care steve and good luck
Rich
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