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ZIPPER STAIRS - a new type of stairway using Nylon-Cement

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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.
 
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Wepwopper12 days ago

I really want to try making some of these. I have 3 acres down the hill.

Thinkenstein (author)  Wepwopper12 days ago
Good luck. The key is getting the fishnet. Let me know if you actually do the project. I never get to see any physical evidence that my teaching is being used, which is the main goal of doing it in the first place.
espdp21 year ago
Fantastic project! Favorite and collected! I know from my experience with ropes that nylon stretches, especially when wetted. Can you get netting made of some other material that is more static to embed in the concrete? I think that might help extend the life of the concrete by reducing the amount of fracturing once a crack starts to form.
Thinkenstein (author)  espdp21 year ago
Nylon has better longevity than many plastics. I don't know what else might work as well. What I would like to see is our plastic trash turned into some sort of plasterable plastic mesh.
Here is where you can get more fishnets.
http://www.nbcnews.com/science/debris-hawaii-ocean-cleanup-could-fill-big-rig-6C10798949
james.rasa1 year ago
they look scary and complicate when drunk ;)
Thinkenstein (author)  james.rasa1 year ago
I suppose that even walking on a flat floor could be scary and complicated if one gets drunk enough.
fretted1 year ago
Insane Genius { my compliments to you sir !} zipper stairs rock my son is building a bag house he's gonna love these stairs

Thanks for a great idea and an outstanding Ible !
Thinkenstein (author)  fretted1 year ago
Thanks. Send a photo if your son uses the idea, It's nice to see people actually using the info.
Toga_Dan2 years ago
Great solution to a steep incline.

On such a steep stairs, I'd like to have a rail or rope to grab. It's often best to descend while facing the slope. Toes are better on a narrow step than heels.

You're a refugee from LA. Did you work on the original "planet of the apes"?
Thinkenstein (author)  Toga_Dan2 years ago
I have never done really steep zipper stairs. When the slope is low, there is no need to angle the steps. The steeper the slope, the more angle. I think you could probably work them into a really steep slope making it more like a narrow slot with steps on either side, narrow in themselves but since you would be stepping more side-to-side, the foot should still fit comfortably. It probably would be fairly comfortable both ascending and descending.

Nope, I never worked on the original Planet of the Apes.
Toga_Dan2 years ago
On such a steep stairs, I'd like to have a rail or rope to grab. It's often best to descend while facing the slope. Toes are better on a narrow step than heels.
EmmettO4 years ago
These are in essence jefferson stairs and are not new. I just built some for a customer. You can see more of them here. http://www.google.com/images?hl=en&q=jefferson+stairs&um=1&ie=UTF-8&source=univ&ei=7rwiTO7bNoOBlAeQrIDsBQ&sa=X&oi=image_result_group&ct=title&resnum=4&ved=0CDcQsAQwAw
The problem with these, and with Jefferson stairs (which are similar, but not the same as these) is: they are for young, able people. Older folks tend to take stairs one-at-a-time, or a couple and then rest. With these, and Jefferson stairs, there is no place to put two feet on the same step (so one remains "level"). As with Jefferson stairs, once you begin, you go till you hit the top. You can stop, but then you're straddling steps with one foot at one level, and one at another. As with Jefferson stairs, these won't pass code in most places. I think they are very cool and took some obvious intelligence to design, but I dislike designs that exclude certain folks. Little ones tend to take stairs like older folks, one-at-a-time, so they are excluded, as are older folks. Also excluded are moms leading up little ones. Perhaps if each tread were lengthened a person could rest on one step easily, which would make it more accessible for little guys and older folks, and parents with kids in tow.

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.
I am one of those people who take normal stairs one step at a time and I am quite excited about this design. It looks like it would be much easier on my wrecked knee and ankle.

As for passing code . . . .
PACW PACW2 years ago
Okay. Instructables seemed to have cut off my libertarian rant. Oh well. Long story short - too much government; too little innovation.
Thinkenstein (author)  DallasDeckard4 years ago
Wow!

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.

You are right, they are 'neato" and perhaps I'd eat my words if I saw them in action. From the photos though, it doesn't look as if it would be easy to stand on a single step, and then move on. as you say, doing so causes a change in "trajectory", which (in my humble opinion) is dangerous.

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!
Thinkenstein (author)  DallasDeckard4 years ago
I'm honored to be talking to a stair expert.

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.
GH 09-12-21 (11) -sm.JPGGH 09-12-21 (12) - sm.JPG
If it's just for you, then I think it rocks! I was interested in it because I'm always interested in different designs of stairs. I thought you were building these for commercial locations.

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.
Thinkenstein (author)  DallasDeckard4 years ago
I'm glad you did bring them up. They are good things for people to consider.

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.
Aren't those basically what BOCA calls an alternating tread
stairway? Those are, last I looked, legal anywhere a ladder
would be legal.


Alternating tread egress is allowed in certain, specific instances. None of them involve public access: penal facilities, industrial/mechanical areas, factory, high-hazard or storage occupancy rated structures.
Thinkenstein (author)  EmmettO4 years ago
Thanks. Yes, the jefferson stairs are similar. The same left-right-left-right idea, only not turned 90 degrees to each other. A much easier design for making it out of wood.
Wepwopper2 years ago
Thanks for the great instructable!

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?

Thinkenstein (author)  Wepwopper2 years ago
I suppose that would depend. You could channel water off to the sides occasionally on the way down, or control the channel at the bottom. Eventually water leaves the cement and flows over dirt. You have erosion there.
claudg19502 years ago
A few more pictures of what may be called -now I learned- a Jefferson stair.

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
2 metal spines.jpgHilltop-08.jpgimg17.jpgsteps-1-600x544.pngsteps-closeup.png
claudg19502 years ago
A very interesting idea. A somehow similar concept -alternating feet- was apparently applied in the images I'm attaching. (Left side shows front views, while right side shows top to bottom views.)

The design with triangular solid rungs seems to be specially applicable to your case.

Thank you for your valuable instructables.
Front View.jpgtaf-stairs-300x256.jpgFrom top to bottom.jpg
luckypalm2 years ago
Have you considered snow/construction fence? The DM504 has a 1-1/4" grid

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.
Thinkenstein (author)  luckypalm2 years ago
Thanks for the suggestion. I think I am pretty much done with major construction now, though.
mgalyean3 years ago
First, I really like the directions your mind takes in your instructables.

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.

Thinkenstein (author)  mgalyean3 years ago
Nylon fishnet is gold. Get it while you can. It stores well if kept out of sunlight. It doesn't stop the cement from cracking, but it keeps the pieces from going anywhere. Once protected from sunlight by the cement, I have no idea how long it will last, but I imagine it will be a long time.

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.
ivan_s3 years ago
great idea ¡¡¡
Outdoor special

TAKuhn3 years ago
I love the stairs they look completely ergonomic. Safety wise the problem with stairs is not generally missing the next step but clipping it with a toe (going up) or heal (going down, yes a pun) that sends a person tumbling so the zipper stair angle in the center gives more than enough room for foot clearince and hand rails of any sort would decrease the chance of falling significantly.
Thank you for a brilliant design.
artcobain4 years ago
 wow! is it you invention? is it easier to climb at that? i think that there should be a new philosophy about stairs in architecture. and this is awesome.
Thinkenstein (author)  artcobain4 years ago
Thanks.  I'm glad you like the idea.  Yes, it is my invention, but it grew out of an old idea of hand holes carved in the rocks for the Anasazi Indians to reach their cave dwellings.  If you expand the small holes until they meet, you more or less get a zipper stair. 

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. 
this is very similar to what is known as a "monk's ladder" stair
Thinkenstein (author)  Lighthouse4 years ago
Thanks. I checked them out. They are similar. It seems like a reasonable concept, putting a step of adequate depth where the foot would naturally go when climbing an inclined plane. By making it a designated left or right foot step, instead of a generic step, you can remove the un-needed side of the step, thus clearing passage for the next foot that has to rise.
this is a monk's ladder i built to access a window leading to a fire escape. i like the idea of using the same concept in the solid stairs you built up the side of the hill. it looks more 'natural' than normal stairs.

monksladder.JPG
Thinkenstein (author)  Lighthouse4 years ago
Cool ladder. Thanks for sharing it.
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