Print PDF
Favorite
Email
Stairways have been a part of architecture for thousands of years. Zipper Stairs are a new type of stairway.
My inspiration for zipper stairs came from a visit to Mesa Verde National Park, where the Anasazi Indians had carved hand and foot holes in the rocks to climb up to their cliff dwellings. Their holes were small, and were probably chipped out with much difficulty using crude tools. If one were to expand the holes until they touched each other, something they did not do, the end result would be similar to zipper stairs.
Stairs are used to climb an inclined plane. They have a vertical face and a horizontal face. As the inclined plane gets steeper, the vertical face gets higher and the horizontal face gets narrower. The higher the step, the harder it is on ones knees. As the horizontal face gets narrower, ones foot eventually doesnt fit on the step, unless the foot is placed sideways, which is awkward. Going up and down traditional steps becomes more dangerous the steeper they get.
Using zipper stairs on the same slope, there are more steps, so the vertical rise for each one is shorter and more comfortable for ones knees. Also, by turning the steps at an angle to each other, one gets the diagonal distance of the rectangle for ones foot, which is longer than the short distance provided by normal stairs. Zipper stairs are more comfortable and safer for steep slopes than are traditional stairs.
This instructable will show some of the zipper stairs I have made over the years and follow one stairway project from beginning to end.
My inspiration for zipper stairs came from a visit to Mesa Verde National Park, where the Anasazi Indians had carved hand and foot holes in the rocks to climb up to their cliff dwellings. Their holes were small, and were probably chipped out with much difficulty using crude tools. If one were to expand the holes until they touched each other, something they did not do, the end result would be similar to zipper stairs.
Stairs are used to climb an inclined plane. They have a vertical face and a horizontal face. As the inclined plane gets steeper, the vertical face gets higher and the horizontal face gets narrower. The higher the step, the harder it is on ones knees. As the horizontal face gets narrower, ones foot eventually doesnt fit on the step, unless the foot is placed sideways, which is awkward. Going up and down traditional steps becomes more dangerous the steeper they get.
Using zipper stairs on the same slope, there are more steps, so the vertical rise for each one is shorter and more comfortable for ones knees. Also, by turning the steps at an angle to each other, one gets the diagonal distance of the rectangle for ones foot, which is longer than the short distance provided by normal stairs. Zipper stairs are more comfortable and safer for steep slopes than are traditional stairs.
This instructable will show some of the zipper stairs I have made over the years and follow one stairway project from beginning to end.
Remove these ads by
Signing UpStep 1The Project Begins
This is the work site at the beginning of the project. There are two basic problems; the stairway, and water drainage, which has gouged out a ravine next to where the stairs will go. This instructable covers only the stairway.
The slope is steep, a perfect place to use zipper stairs.
After the stairs are carved into the dirt, and the ravine is filled, everything will be covered by a layer of nylon-cement. Nylon-cement is a combination of nylon fishnet and cement, a material I developed many years ago, and have built my whole house out of. You can see one project I have done with it on my road repair instructable, http://www.instructables.com/id/ROAD-REPAIR-with-NYLON-CEMENT/
Think of nylon-cement as you would a layer of fiberglass. The fishnet replaces the glass cloth, and the cement replaces the resin.
The slope is steep, a perfect place to use zipper stairs.
After the stairs are carved into the dirt, and the ravine is filled, everything will be covered by a layer of nylon-cement. Nylon-cement is a combination of nylon fishnet and cement, a material I developed many years ago, and have built my whole house out of. You can see one project I have done with it on my road repair instructable, http://www.instructables.com/id/ROAD-REPAIR-with-NYLON-CEMENT/
Think of nylon-cement as you would a layer of fiberglass. The fishnet replaces the glass cloth, and the cement replaces the resin.
| « Previous Step | Download PDFView All Steps | Next Step » |
Concerning your comments on "traditional stairs", it's all in the design. If someone tries to build a stair with a very short overall run, the only way to accomplish that is to increase the individual rise of each tread or decrease the tread length. However, there are codes governing this and they stipulate that the rise and run of each tread falls within an (easily scalable) specific height or length, which (by default) limits the slope of any stair. No stair built today would ever pass code where (as you say) "ones foot eventually doesnt fit on the step, unless the foot is placed sideways, which is awkward." Treads must be a certain length (length here is measured from one rise to another). The IRC stipulates the following codes: "10” minimum tread length, measured from nose to nose of adjacent treads, is required. IRC RR 314.2 16. Risers shall not measure more than 7,3/4”. IRC RR314.2 17. A maximum 3/8” differential is permitted from the largest to the smallest tread, or the largest to the smallest riser. IRC RR314.2" These are easily climbed by the young and old alike.
Your design seems as it is meant (primarily) to solve the problem of maximizing space. By placing more treads (and hence individual rises) in a smaller space (a shorter overall run) it maximizes space, and it is safer than someone building something out of code with unsafe rises or tread lengths - no doubt about that. I just don't see why either need be an option. Even in your example here, you have more room for a longer run, why not just build a standard stair with a safe rise and run? Yours are certainly safer than a steep rise or shallow run, but why do either? It's cool, but it limits accessibility and trades safety for a high "neato" factor. I suppose if someone were building it for themselves, and had limited depth for a regular run of stairs, this might be fun, but what about when they get older? One could just as easily build a circular design, that handily accommodates a limited depth.
As for passing code . . . .
Most visitors, including older ones, comment about how much more comfortable these stairs are than standard ones would be, given the same slope.
These particular steps have plenty of room for two feet to stand and rest on them.
You should see kids climbing or going down them. They take a step, turn, take a step, turn, take a step, etc. It all looks very safe and manageable to me. Plus, with the shorter rise for each step, that makes it easier for kids, and old people.
In matters of safety, with standard steps I imagine a kid going thumpety, thumpety, thumpety all the way down. With zipper stairs, I would imagine a zig-zag trajectory, with probably a thumpety, thumpety, stop. Fortunately, no children have ever fallen on the stairs to test this theory.
As far as building codes go, I'm sure they are there for a good purpose. Stairs have been traditionally made with other building techniques, however, and those are the techniques the codes have been built around. These are sculpted stairs, and what they do they do well, if I do say so myself.
Circular design stairs have a high "neato" factor, also. I find triangular stairs dangerous in comparison to these basically rectangular ones. The "neato" factor in itself is not bad.
I'm glad to hear no child has ever fallen, particularly if a lot of kids have climbed them.
I can assure you that the stair codes are constantly being revisited, challenged and (very rarely) changed based upon many, many local and national meetings. I, myself have attended and presented at local meetings for changes to the codes. The inspectors and officials that are responsible for setting and enforcing the codes are well aware of the different designs (including Jefferson stairs) and have rejected these as unsafe for various reasons. I was actually at a code meeting at the local level in a city (suburb) that was using codes to hinder construction. They were making codes so restrictive that it took either too much time or too much money to make building feasible. The code in question was "continuous rail". Most cities interpret it to mean that the handrail must run from the first rise to the last rise with no breaks in the rail, unless there is a change in direction (at the turn) whereupon a newel (post) may be placed. Some cities don't allow a newel (post) and the rail must be continuous. However, this city interpreted "breaks" to mean that the handrail couldn't have *any* cuts in it. For example, say there was a small opening rake and then a landing with a 90 degree change in direction, which continues on for another rake run, the rail could not be cut and pieced together to create a continuous rail. They interpreted it to mean the rail had to be uncut, which meant it had to be bent rail, which was impossible in many situations (which is what they wanted). So, homebuilders began to design only stairs that were circular or straight with changes that could be covered with bent rail (a real feat in some cases, I don't mind telling you).
At any rate, at this meeting a landscaper presented his case for steps up a walkway that were similar (in some ways) to your design, although his were much less elegant. He presented, they laughed, we moved on. They've seen other designs and rejected them. I presented at the same meeting with a representative from one of the spiral stair companies (the kind that sell as "kits") because of a problem they were having concerning the way the two types of handrail met at the top. The spiral stairs were built with either iron, or wooden handrail that was not available from any stair part supplier. The inspectors were red-tagging it because there was a difference in the profile of the handrail, which they interpreted as a "break" in the rail. We presented a compromise which they took under advisement, which must have worked because the inspectors quit red tagging us. Point being, they know the different designs that are out there, and they reject them as "unsafe".
I'll tell you why your stairs would be rejected, because only one person may terminate at a time. This is a big no-no in the construction of stairs, particularly a commercial installation (which your stairs have been built for, unless I'm mistaken). Commercial codes are more restrictive than residential codes, but one of the cardinal rules there is that case must be wide enough, and the treads designed such that they accommodate more than one person. This is important, for example, in case of a fire. You can't have one incapacitated person clogging up the entire egress for everyone else. There must be room to tend to that person, while the others continue to exit. The other reason why they would be rejected is for the reason I already mentioned, a person must be able to take one tread at a time and be able to stop, with both feel on the same tread (facing forward) in any installation (even a spiral one). For folks to do that on your design, they would have to make a (rather marked) change in direction, basically turning 45 degrees each time. That is simply unsafe.
What you say is true, smaller rises are easier for older folks to climb, but that is just one part of the puzzle to making a safe, scalable stair. Smaller rises are easily accomplished in a traditional stair, with standard treads, as long as there is enough room for the overall run. You see these types in some cities, where there are many long, wide treads and small (less than 5") rises built in concrete. There is one in a city center near me with a fountain in the middle.
I agree with you, the neato factor is important - not more important that safety and accessability - and sholud be considered any time anything is designed for humans to use. I built stairs for 20 years and constructed some pretty neato designs myself, though none as radical as yours. I put up some of the more traditional ones on my Flickr page here:
http://www.flickr.com/photos/areasonableman/sets/72157602540013509/
In the future I'll put up ones that were more unconventional, including a stair I did for a man that was WAY into fish, which incorporated saltwater tanks in the walls, custom, metal balusters shaped like dolphins and a huge rail that undulated like waves. The problem is, in many of the more custom homes, the homeowners either make you sign a contract prohibiting you "sharing" the design, or posting pics. Sometimes it helps waiting a few years for them to decide no one is going to heist "their" (my) design.
The most neato thing you've ever done is add testicles to a water spigot. Hands down. It took real balls to do that!
stairway? Those are, last I looked, legal anywhere a ladder
would be legal.
Unfortunately, your flickr.com photo link did not work for me. I would like to see your unusual designs (especially the ones you can't show me.)
Back to the zipper stairs. You can put two feet on one stair while facing forward. If necessary, you just put one foot slightly in front of the other one. That way, both feet get the full diagonal distance of the stair.
If one person stands on one stair, that leaves the other lane open for passing. The person in a hurry just has to take a 2-step step. I have done that sometimes, playing with younger upstarts who want to race me. I catch up and pass them by using only the steps in one lane. (I'm in pretty good physical shape to begin with.)
The zipper stair concept is flexible. At a low slope, there is no need to use them. Standard stairs are fine. As the slope increases, the angle at which the stairs meet changes, getting more and more acute. Although I have never had to go beyond 90 degrees, theoretically you could climb an almost vertical crack in a wall, with long narrow steps on either side of you.
Hand railings are a problem I have not dealt with much yet. In zipper-like stairs on top of my house I once put an overhead hand rail down the center of the stairway, attached to the overhead trellis. It is for my use only, not for visitors.
Zipper stairs are easy to carve into the dirt and line with nylon-cement. I imagine they would be a lot more difficult as a woodworking project. I have done an above-ground set of ferro-cement zipper stairs at my guesthouse, however (photo attached). The geometry of the rod work is a bit tricky, but fun.
My construction is not commercial. It is part of my home and private guesthouse.
The thing I like about the stuff you build is, there is no precedent for it. I'm sure you hear this a lot, "Oh, you can't do that" - or, "That won't work that way". I've heard that so many times it makes me boil. I've gotten to where when someone asks why I need this or that part, or some product, I don't tell them or I just make something up, because I don't need some pneumatic tool salesman to tell me that I can't use brass fittings for a glue bottle or whatever.
When you innovate - as you do - you always get someone telling you "it won't work" or "that's not right" or whatever. I didn't mean to turn into that guy. If I wasn't interested in the design and the application, I wouldn't have brought up the issues with it I did.
It is too bad that one sometimes has to live in the jungle to have the freedom to experiment. People and all their "correct" ways of doing things do get in the way sometimes.
I love the natural look of these and they would definitely be easier on my knees. :)
I could sure use a set of these down my hillside to stop erosion and give me access to my 'back 40'. :)
It looks to me as though it channels water down the center. Does that create water damage at the bottom?
These images follow the alternating steps concept. However, the 45 degree angled steps you created for your project seem to be uniquely yours. Well done
The design with triangular solid rungs seems to be specially applicable to your case.
Thank you for your valuable instructables.
http://www.discountfence.com/snowfence/snow_and_barrier_fence_index.htm
I recently came across your site after looking at the magnesium ferrocement on Owen Geiger's earthbag blog as nylon cement is mentioned.
The zipper-stairs are just plain elegant. The minute mentioned Mesa Verde I knew exactly what you meant. The idea of joining the foot/hand holds into stair-like structure is very cool. Major kudos for that.
As for the nylon-cement, what is the oldest structure you have made of it and how is the nylon holding up? Or, to put it another way, do you feel the net is only necessary as a structural element until the cement cures, or do you think it provides 'rebar' like strength even after cure, and if so, for how long? I'm just looking for gut answers here, nothing scientific. I'm thinking the nylon would not last as long as galvanized chicken wire, even embedded in concrete, but am not sure that really matters if the crete is thick enough and "domed/arched" enough to provide its own structural properties. I live on an island in the NC sounds and old fishnet is always washing up somewhere. My 14 y.o. son recently made a new net for his basketball hoop out of some he'd found while oystering.
I'm guessing that some of my thin nylon-cement layers on the ground must be around 20 years old now, at least. It performs as expected. Protected from the sunlight it lasts a long time. I got used fishnet to begin with, so most of it had sun exposure and was not 100% strong to begin with. It is hard to measure any weakening over time. If it doesn't tear, though, it is functionally just as useful as 100% strong new fishnet.
On the stairs, it helps to make the cement a little thicker, because coming down the stairs, one's impact is greater than it normally is in walking. The front face of the steps benefits from extra thickness, because the edge of the stairs takes the most impact.
The fishnet does not provide rebar-like strength. It stretches, whereas the rebar does not, but the rebar and chicken wire can rust, which the fishnet does not. On the ground, I prefer to avoid the use of iron completely.
If the cement work gets too many cracks, you can always pressure clean it and "paint" it with a layer of colored cement -- returning it to like new appearance.
Outdoor special
Thank you for a brilliant design.
With standard stairs on a steep slope, you get a high rise for each step (knee bends more), and less space for the foot. By turning the stairs at 90 degrees to each other, you get to use the longer diagonal distance for the foot. Also, there seem to be more steps, so the rise is less for each step.
www.mortarsprayer.com
I have seen something similar to this, built out of metal, in a zoo (behind the scenes of course). They used it in their giraffe area (very tall, but not a whole lot of horizontal space to work with). I wish I had taken a picture now.
These are really neat and look very nice in the outdoor setting you have made =)
What great Info. I would like to build a shelter and boulder for my goats. I live in the flat lands of southern Illinois. Do you have other pictures of this structure completed.
Thank you
HR
P.S. I lived 3 doors down from Bucky Fullers 1st dome in Carbondale, Illinois. He taught there long before i was born but his legacy is still there.
Just came across this and think it solves a problem I have been wanting to overcome for years. Thanks for a really great instructable.