My recollection is that the code for a ramp was/is 1:12 slope under the UBC. The IRC permits a 1:8 slope. I have a very elderly client who wants a ramp in a space that would permit about 1.6:12 slope, a little more than the 1:8. I know it’s splitting hairs, and I’m sure I can persuade him to stretch it a bit, but anyone out there who has built a ramp recently? I want this to be an absolutely comfortable walk for him. The public ramps I’ve checked out all seem to be the 1:12 slope.
Second Q: he wants a plywood surface and thinks that ACX ply will be acceptable if painted and maintained. I’m skeptical.. I think marine ply of some sort, maybe a 13-ply 3/4″ is the right thing. Paint with some sand mixed in…? I’d rather use cedar or maybe even a composite decking, seeing as it has to bear almost directly on grade at the bottom, and invitation to rot.
Replies
I'm in agreement with you on both points....I too believe a ramp need a 1:12 slope, and I'd try and convince the client into using cedar or composite decking material.
Even if it doesn't rot...plywood is going to get and remain wet.
J. D. Reynolds
Home Improvements
as an aside, good on you for caring enough to try to do it right even if that means pushing back on what the client's requesting.
Most accessible codes we see allow 1:12 as a maximum slope. MA residential code allows 1:8 for a ramp, but requires 1:12 if it is for accessibility purposes.
You mentioned you wanted this to be an easy walk for him. Have you considered an accessible stair instead?
Call up the locak AHJ, they'll often have the answers they check the plans against.
I want to remember that "flat" work is limited to 1:24; ramps max at 1:12. That you need railings if the ramp is more than 10' long, or more than 6" of height change. In-line Landings are 2x width, too, IIRC.
David
I have built a few wheel chair ramps here in Charleston. I have used marine grade plywood which was painted with an alkyd exterior primer then two top coats of non-skid deck paint by American Traditions. The top coats of paint have held up very well considering the irrigation system keeps it wet on a daily basis. I placed a PT 2 X 6 at ground level and the bottom of the plywood ramp rest on this. The ramp is in ground contact and after two years does not show any rot at this point. I prefer to not have ground contact but you do what the client wants and what the terrain allows. I use 1/12 as a minimum 1/16 is better. I have attached a link that might give you some help. Look at section 4.8. Hope this helps.
http://www.usdoj.gov/crt/ada/reg3a.html#Anchor-Appendix-52467
Mark
I don't know if what Wisconsin's code is based on but I did a ramp a couple of years ago that had a section at 1 in 9.9, and another section at 1 in 10.
1 in 12 is a commercial code, 1 in 8 is max for residential. There are some other considerations too. If the ramp is elevated more than 24" it needs a guardrail, which is going to be at 36". A ramp between 1:8 and 1:12 needs a handrail on each side, between 30" and 34", and there must be 36" of clearence between the rails. A ramp that is 1:12 or less can have just one handrail. So design appropriately for those, because I didn't, and ran afoul of the inspector by about 1/2". (made thinner rails so as to pass inspection.)
The explanation I recieved for having 2 handrails was that a wheelchair bound individual would need to grab both rails to puill themselves up the ramp, whereas at the lesser slope they could roll themselves up.
The customer I built it for was about 65 and had a stroke. At the time his 65 yr old wife was able to handle him in his chair on that slope, though they only went out in good weather. Now he has a powered chair and can work it on his own.
I used treated deck boards, and put anti-skid tape on them.
As an aside, this customer had only been carried out of his house once a month to go to the doctor. I was not even done picking up my tools and he and his wife went down it and went for a walk in the neighborhood. First time he had been out on his own in 3 months.
Bowz
Further details and some answers:
The owners are a married couple. He is using a wheelchair and she is not, so he will be rolling up and down the ramp and she will be walking. He's getting a motorized wheelchair and I think those things are fairly powerful, so the slope for walking is more my concern. Anyway, this is an accessibility ramp.
The AHJ here appears to be enforcing the IRC but has not actually adopted it. Long story. The owner does not want a permit, mainly because the AHJ takes forever to issue them, i.e 12 weeks or so. It's ridiculous, expecially when something like this could be an over-the-counter permit in so many places. Anyway, I have no real problem with building this without a permit because it's 100% inspectable after the fact and as long as I build it to the more stringent code reqs I know I am covered.
The ultimate goal is for him to access his lower-level workshop. This will involve rolling down the ramp, doing a 180, and then rolling down a gravel path to the door. The gravel is steeper than the ramp by a good bit, maybe even 2:12 or so. I have major concerns about that part, but I don't have control over it, aside from maybe refusing to get involved at all.
There is a wooden stair that leads directly down to the door in question. In an interior application this could be handled by an electric stair chair, but I've never seen one outdoors. I'm sure there are outdoor chair lifts that go straight up and down, but they can't be cheap. I think if cost were no object I'd get an exterior chair lift, demo the stairs, and install the lift in their place, with a big concrete landing at the bottom. I can't imagine those lifts are less than $10K.
The ADA federal law requires 1/12 for all public places and commercial access. Private homes is another story entirely.
I built one tha a HO had requested at 2/12, but I stretched #### to almost 1/12 because I know his aunt could not mount that pitch alone.
He bellyached for a day, paid the bill, and ever since then has reminded me how glad he is that I did it right.
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