I’ve seen pictures of a weird kind of stair-construction that is for steep and tight-space stairs. The tread does not extend the full length across so that it is one half stair on the left followed by one-half stair tread on the right and so on. The people that showed me pics of theirs years ago really loved them and I think that they somehow make steep rises go easier.
Does anyone here know what these are called so that I could search for pics of them and info on them?
thanks!
nb
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Replies
I think they're called "Ship ladders" or "ship stairs"
I have heard them called Submarine stairs. An ex BIL of mine has a flight that is cool, the treads are in the shape of a large shoe sole.
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Try googling alternating tread stairs. I don't think they will meet code in most areas though.
Tom
Douglasville, GA
Here's what I found on it. I don't really get WHY they are easier. I'll keep looking though. Thanks for helping me to find them!
nb
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Where there is insufficient space for the full run length of normal stairs, alternating tread stairs may be used. Alternating tread stairs allows for safe forward-facing descent of very steep stairs. The treads are designed such that they alternate between treads for each foot: one step is wide on the left side; the next step is wide on the right side. There is insufficient space on the narrow portion of the step for the other foot to stand, hence the person must always use the correct foot on the correct step. The slope of alternating tread stairs can be as high as 65 degrees as opposed to standard stairs which are almost always less than 45 degrees. The advantage of alternating tread stairs is that people can descend face forward. The only other alternative in such short spaces would be a ladder which requires backward-facing descent. Clearly alternating tread stairs may not be safe for small children, the elderly or the physically challenged. Building codes typically classify them as ladders and will only allow them where ladders are allowed, usually basement or attic utility or storage areas not frequently accessed.
The image on the right illustrates the space efficiency gained by an alternating tread stair. The alternating tread stair appearing on the image's center, with green-colored treads. The alternating stair requires one unit of space per step: the same as the half-width step on its left, and half as much as the full-width stair on its right. Thus, the horizontal distance between steps is in this case reduced by a factor of two reducing the size of each step.
The horizontal distance between steps is reduced by a factor less than 2 if for constructional reasons there are narrow "unused" steps.
There is often (here also) glide plane symmetry: the mirror image with respect to the vertical center plane corresponds to a shift by one step.
Alternating tread stairs were invented by James Lapeyre. He received US patent 4,509,617 on April 9, 1985.
Alternating tread stairs have been in use since at least 1888.
"easier" than what?I thought this was funny:"Alternating tread stairs were invented by James Lapeyre. He received US patent 4,509,617 on April 9, 1985.Alternating tread stairs have been in use since at least 1888."Was that a typo (1985?) or just another example of our failing patent system?
Not sure about easier. I'm sure they are easier than the ships ladder they can replace but surely not easier than normal stairs. They are dangerous in that you HAVE to start out on the correct foot. hile that may be easy for someone familiar with the home, guests may find it a problem. Also anyone that can only go up one step at a time will have a big problem with them.Tom
Douglasville, GA
They are easier because they reduce the felt rise to half of what it would otherwise be. Each foot still has to travel the full rise, but since these stairs are climbed by alternating from foot to foot, the effort is only that need to raise one's body by half of the distance to the next same-foot step.
It would be interesting to cut a set for a kid's playhouse, or to reach a loft in a cabin, for instance. I believe four stringers are req'd, with the middle two staggered then face-glued together.
There is a simple illustration in the Stairs section, p. 165, of Rob Thallon's "Graphic Guide to Interior Details for builders and designers", Taunton Press, 1996.
Thallon refers to them as space-saver stairs, and says that they "provide the most efficient use of floor area of any stair configuration. This stairway, which includes a separate stairway for each foot,...is not allowed by code as an egress stair."
Taunton has another book in this series which deals with exterior details. Both are an excellent resource to prevent/solve problems.
"They are easier because they reduce the felt rise to half of what it would otherwise be. Each foot still has to travel the full rise, but since these stairs are climbed by alternating from foot to foot, the effort is only that need to raise one's body by half of the distance to the next same-foot step."
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This seems nutty to me because you are STILL 'lifting' the same amount of weight (your own body weight) the same distance! There is NO getting around this no matter how unique or well designed the stairs are! Physics is physics. Maybe I'm 'daft' (as gramps used to say...) but I STILL do NOT see how they could be advantageous in terms of effort.
I'll keep looking into them though. I like what Thallon says ... wish I could get an online look at that section of his book!
nb
Yes, you are lifting your own body weight the same overall distance - say from one floor to the next - but you are doing so in small increments. A little bit at a time is less effort.
Same idea when lifting a heavy beam into place. It is easier to lift it a couple feet at a time, rest it on a temporary support, lift it another couple feet to another rest, and again, till it is sitting in its pockets.
You already know how the more steps there are in a given stairs, the more risers there are. With more risers, the unit rise figure is less, and each step up becomes easier.
You also know how small staircase openings force carps to build steeper stairs (with fewer but taller risers) than might otherwise be comfortable, but there's no choice if head clearance is to be preserved. Well, the stairs you asked about are even steeper (someone said as much as 75 degrees), while still maintaining a reasonable unit rise, provided you climb one side with one foot, then the other side with the other foot.
Recap: Thallon spoke of these as being two stairs side by side, offset to each other. On their own, it would be like climbing a narrow ladder. Combined, they feel half as steep.
Look for pics in archy/reno magazine features on 18th and 19th Century homes, esp. from New England states.
Edit: I've climbed a set in a 19th century farmhouse. They look really steep - because they are - but they climb much easier than they look.
Edited 9/11/2006 10:21 pm ET by Pierre1
I'm still not sure what you are comparing these to in terms of 'easier'.They are not easier than a regular set of stairs. However, they are easier than a traditional ladder...namely because you can descend them just like a normal stair case.
Also: wonder how you'd figure the needed overhead hole size to build these. And, hell ... how you'd build them! Need some sort of 'guide' to look at.
n
I have a book called:Techniques OF Staircase Construction
By Willibald Mannes
Published by Van Nostrand Rienhold
ISBN 0-442-26086-5
Library Of Congress 86-9252It is a 1986 translation from the 1925 German original. There are, on page 17, some pictures of models and actual stairs along with some illustrations of both straight and spiral, Space-saving stairs. Maybe you can find a copy at the library.
One simple way to build them would be to build two very narrow sets of stairs, and then fasten them together. I've seen these stairs built with three stringers, and all the steps routed into the stringers. i.e, the center stringer rose up above the tread a little, and treads were offset from one side to the other.
Figuring the headroom shouldn't be too difficult- measure up about 7' from the forward edge of the treads.zak
"so it goes"
One simple way to build them would be to build two very narrow sets of stairs...
dayam ... I'll have to cook on this. I've got the perfect situation for these stairs .. extending up to a 'less than 200 sq. ft. mezzanine' which, by code, is ok for these. If they really make the rise 'easier' then I'd like to try them. but I'm an exTREMEly visual guy ... a pic or two that showed not HOW to build them but just a good set of hand built ones .. would really get me goin. I'll hafta keep looking around. All I seem to be able to find thus far are very formally manufactured examples that really don't float my boat. for example: http://www.arkestairs.com/images/customer_pics/peter_karina1.jpg
Again ... I'll have to keep poking around.
thanks!
nb
Edited 9/12/2006 12:20 am ET by newbuilder
Figuring the headroom shouldn't be too difficult- measure up about 7' from the forward edge of the treads...
it's the size of the overhead whole that I see problems with in pre-figuring. If I've got a 9 ft. rise (which I do), I can figure out that that is 10 stairs of 8" depth and 11 risers of 9 13/16". OR ... 11 runs of 8" and 12 rises of 9" ... and then go about figuring the headroom. But with these stairs I don't get what the 'formula' would be. I guess I just don't understand this design yet.
nb
I've been looking at google images, I've found a few under "altenating tread stairs". Here's one link to a nice set: http://jitterbug.smugmug.com/gallery/678276/1/29368267zak
"so it goes"
and another, not a very clear picture, but simple plan.
http://www.uniquespiralstairs.com/images/gallery/Alt_tread_stair2.jpgzak
"so it goes"
Wow ... these are great pics. But it doesn't look like these folks really took advantage of the benefit of keeping them in a very confined space ... they almost look like regular stairs .. sizewize! Love the unusual look though. I'm building my situation out so that they'll only be 20" wide. I've to 9' between floors. I could go anywhere from four to a max of about 7 feet run .. would much rather keep it to 5 or 6' max. Hmmmmm....
I'm not sure exactly what the rise/run would be, but I'm guessing you could think about one side of the stair at a time. So you could double the riser for a given tread depth, and end up with something like 10" run, 16" rise. You don't need to find where a given tread ends, you could just draw the line connecting the tread fronts. 7' down the stairs is 52.5" out. 5' hole might do fine, it would feel roomier with 6' or so.
Sketchup would be perfect for drawing this up, but I don't have time tonight.zak
"so it goes"
You still want your risers to be in the neighborhood of 7-8 inches
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well, 14" - 16". I guess it's the same thing, just depends on how you are measuring them. ;o)
ok
Welcome to the Taunton University of Knowledge FHB Campus at Breaktime. where ... Excellence is its own reward!
Lapeyre Stair makes alternating tread stairs for industrial applications. The guy who invented them also invented the shrimp peeling machine. I met him back in the 70s, when he was still living.
http://www.lapeyrestair.com/
This company sells alternating tread stairs for residential applications:
http://www.arkestairs.com/karina.php
Billy
<I met him back in the 70s, when he was still living.>
That would go without saying
;-)
Forrest
<I met him back in the 70s, when he was still living.>
That would go without saying
;-)
======================
O.K. -- I am busted!
Here are his patents, if someone needs to know to contruct the stairs.
http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.htm&r=0&p=1&f=S&l=50&Query=in%2Flapeyre+and+spec%2F%28alternating+and+tread+and+stair%29&d=PALL
Billy
Is there a way to get the drawings to show on the patent site?Tom
Douglasville, GA
Yes, you need to download their special viewer and then you can see the drawings.
http://www.uspto.gov/patft/help/images.htm
Billy
ThanksTom
Douglasville, GA
No problem -- Lapeyre was an amazing inventor. In addition to the stairs, he invented the LED printer (using a strip of LEDs instead of a laser), shrimp peeling machine, shrimp deveining machine, computer keyboards, the electronic compass, and others. He saw problems where others did not and he came up with ideas to fix them.
When he was a teenager out on a shrimp boat he noticed that sometimes when he stepped on shrimp with his rubber boots in just the right way, the shrimp would be squeezed and pop right out of the shell. So he invented a machine with rubber rollers shaped and spaced just right to pop shrimp right out of their shells. No way to compete peeling shrimp by hand when you could dump bucket-loads of shrimp into his machine and get peeled shrimp out of it...
Billy
I'm confused as to how he 'invented' these when they were in use a century before the patent filing.
That's a good question, and a common one.
You don't get a patent on a concept -- you get a patent on specifically claimed inventions. Just because stairs are known doesn't mean you cannot patent new types of stairs. Just because alternating tread stairs are known doesn't mean you cannot patent new types of alternating treat stairs.
The U.S. Patent Office isn't perfect (and they make a lot of mistakes), and they don't necessarily have access to all of the prior art in the world. The fact that Lapeyre has a number of patents on specific claimed alternating tread stair inventions speaks for itself, but in the courts people can and sometimes do invalidate claims in the patents.
Billy
Here are a couple of .TIF drawings from the patent on wooden alternating tread stairs.
Billy
The other posts have you pointed in the right direction for Alt tread stairs.
I wanted to mention that I think that one of the codes may allow them for access up to non sleeping "loft" areas of 200sqft or less.
Perhaps someone with a better memory can comment to this?
Here is the reason that are safeer in some ways -
When you go up, facing the steps, it makes little difference.
But when you go down a typical ship ladder, you have to turn aroundm hold the rail, and back down - not the safest for all peole. Your sight is limited as to where you are puitting your feet, and since each full width step is partially below the one above it, your shins may be hitting.
But when you have an alternating tread on a steep ladder type stair, you can confortably walk down them facing forward, seeing where your feet are being placed, and can even carry items with you
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I've also heard of alternating tread stairs reffered to as "Jefferson stairs" because Thomas Jefferson had them in the house he designed (Monticello?). A very simple way to begin thinking about the design would be to create two narrow flights of stairs, each with normal runs but having twice the rise of regular stairs. Set A. would begin with a "half" rise (or normal step height ) and set B. would have a "full" (or double the normal) height step at the bottom.
If you install the two side by side with set B. pushed back the distance of one "run" , you've got your alternating steps. The treads themselves can be installed to overhang the risers - not just on the front but into the plane of the adjacent flight for a more integrated look and feel.
Try a search for the "Jefferson stair" and you'll be, as they say, "movin' on up"
I have heard them called cape cod stairs. It's nice to know that there is yet another thing out there that we've developed out of necessity that has been patented by someone else. We have done three different types of this stair. One is boxed in and has 12 inch treads with 15 inch risers. This is the easiest to use. The other two had an exposed center stringer. One had bolt on ledgers for the treads and the other one had morticed treads. I think that one looked the best but others have disagreed with me on that.
Regardless of what type you use, I feel it is very important to have a hand rail on both sides of the stair and to use them. The most dangerous aspect of the stair is if you get complacent in their use and forget to start on the correct side. That first step then becomes a 15" drop which can lead to a tumble if you don't catch yourself on the railing. Ask me how I know.
The boxed version I did had a bent tubular stainless rail system with tempered glass infill panels. It looked pretty good. I'm sorry I don't have pictures for you. I can get one around the first of October if that will help.
I did my first in 1982. The second in 92 and the last one in 2000.
I have heard them called cape cod stairs. It's nice to know that there is yet another thing out there that we've developed out of necessity that has been patented by someone else. We have done three different types of this stair. One is boxed in and has 12 inch treads with 15 inch risers. This is the easiest to use. The other two had an exposed center stringer. One had bolt on ledgers for the treads and the other one had morticed treads. I think that one looked the best but others have disagreed with me on that....
I would LOVE to see any pics of this you may have ... either posted here or emailed.
Thanks! They sound GREAT!
Teri