Need exterior stairs total run 55 feet. Total rise about 150 inches. Planning three landings, almost 6foot long each. Thus each stringer section will do 50 inches rise, and almost 13 feet run. That’s about 1 in 3. Thinking of about 6 1/4 each rise w 20 3/4″ run. Anybody had experience w this kind of very low slope on steps? Basic stair rules just dont apply w low rise stairs, but comfortable stride is whats important. (And lets leave code/inspectors outta the equation, too)
Thanks
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Replies
You might Google "Low
You might Google "Low slope-long run stair design. Also Halting walk stair design.
There are various rules of thumb. One simple one is that rise + run should equal 18 inches. This works fairly well all the way from a ladder to a flat walk (though there are other formulae that will produce slightly different results).
Thanks, dan, but ive found that the rules really dont apply for under perhaps 6 1/2" rise, at which point you start to feel constrained. I checked dr google, but very little helpful there-- except one guy who said he played around a lot with his treads, and was really comfortable with 24, 25" with a 5 1/2" rise. And I've checked some low slope stairs (outside public buildings, for example) and noted that low rise needs a good long run per step. But havent found any "standard" ratio
Our deck has stairs with a 6"
Our deck has stairs with a 6" rise and 12" run, and that is quite satisfactory.
Rythm
I've built landscape stairs with about 18 - 24" treads with 4" rise. I think that when the rise gets small enough the run needs to be goverened by a nice step and not the rise. Tread width needs to be such that each foot lands at the same spot on every tread. That can mean one pace per rise or two. You need to maintain a natural rythm to your gait.
The thing to watch out for is getting the run too long, such that folks with shorter legs have to take a half-step on each tread. Better to err a bit on the short side, since it's easier for a long-legged person to simply take a slightly shorter step.
That said, I'm recalling that one of the more complicated formulas worked out to about 24-28" on the flat. There probably is more info out there on the Interweb somewhere.
couple of points
Two points to consider:
1. A comfortable stride is generally a safe stride. Code addresses safety and is why you should always consider it in the equation... even if it's not mandatory.
2. What material are you considering fabrication your landscape steps/landings out of? This may dictate your rise unless you're planning on the time and cost of customizing your riser material to fit your exact goal.
BTW, Dan, ladders and flats do not fit the standard "comfort "rules of thumb for stair combinations. For one, ladder rung rise/run combinations at safely pitched ladders aren't at 18" ...and flats do not involve a rise component which renders that a moot point*
* That would be like saying the speed of a greyhound is comparable to a thoroughbred whenever greyhounds run in the Kentucky Derby.
Age old stair forumla ...
2 risers plus one tread = 24"-27" (often the outlined in many codes)
so, if you had a 4" riser, a comfortable tread woud be between 16 and 19". 2 (4" riser) + 1 (16" tread) = 24" and 2 (4" riser) + 1(19" tread) = 27".
3.5" risers would yield treads between 17" and 20"
Also, many code jusitdictions have minimum riser heights...often 4"
If it were me, I would increase the lenght of the landings and stay within the formula above...it's proven over many years to provide comfortable stair riser and tread combinations.