Geodesic Domes are awesome.  This Instructable will show you how I built a 20' dome for about $250, with the majority of that cost being the greenhouse plastic ($167 with shipping.)  That's right, the structure itself cost less than $100!  I will also write about what is wrong with this design, how it came about, what I learned from it, and what you might want to do if you're building your own.

Buckminster Fuller wanted his dome houses to be cheap, quickly constructed, and portable.  Yes, your house was supposed to be able to be picked up with a helicopter and dropped off somewhere else!   The Marines experimented with it in the 60's.  There are pictures of domes being flown around.

My purpose for building domes is the same as Bucky's:  to save humanity from extinction.  We are currently building houses the same way as we did thousands of years ago.  Bucky said we would adopt his new technologies only when it was absolutely necessary.  Well, the time has arrived.  Here is why YOU should be living in a dome:

1)  They use far less material than a square building
2)  They are much stronger, domes have withstood hurricanes and tornadoes, even a nuclear blast 
3)  They use less energy, the oft quoted amount is 30% less, but it goes up as the dome gets bigger

I am submitting this as part of the "Win A Home Fabricator" contest.  If I had had one when this started, it would have shaved days off of construction and lots of frustration.  My next dome will be made out of bamboo, and hopefully use home fabricated vertices (the connectors between the wooden struts.)  So if you like this Instructable, please rate it highly so I can make a better dome next time, and work toward that goal of saving humanity from itself.

Step 1: What type of dome

There are many choices in dome construction.  I chose to build a 3/8 3v dome to keep the complexity low.  This is where the 'designed on a computer" part came into play.

First, I used a program called Dome Designer to play with raw material lengths.  It is very useful in calculating the amount of scrap that will be produced, and letting the user experiment with different dome frequencies and sizes.  Unfortunately, it has a tendency to stop working, and then needs to be reinstalled in order to start again.  Part way through the project, it stopped accepting my license key, and the creator never returned my emails.  I wasn't about to spend another $100 on a program that doesn't work, so it was back to the web.  In the end, everything I needed was online.  The scrap length didn't matter on a dome this size anyway, so it was no loss.

The design tutorial that comes with Dome Designer was actually one of the most useful things I got out of my $100.  In it, they point out that most domes are overbuilt.  People making a house are used to using 2x12" boards, and think that it should naturally be the same with domes.  

This is not the case.  The stress that is put on dome struts is actually tension, instead of compression.  Picture a drinking straw, standing vertically.  Now put a stack of books on the straw.  It immediately bends over and drops the load, breaking if it were something like wood.  But what if you were to suspend the books from the straw?  It could hold them until the end of time.  This principle applies to domes, all of the force exerted on the struts is pulling, not squishing.

That's why I built this dome out of 1" (which is actually 3/4" in the real world) sticks, weak and many cracked.  I wanted to see if they could hold up.  More on the results of that later.

These are the most useful online tools I used:

Desert Domes has a number of great resources, the Dome Calculator and Reverse Dome Calculator being my most used.  It is helpful for figuring out the length and number of struts, and number of vertices needed for different frequencies of domes.

Then I used this diagram during assembly.

Dome frequency is basically the number of triangles that exist in the dome.  The higher the frequency, the stronger the dome, and the more complicated and more materials you will need.  The one pictured is a 3v (frequency 3) 3/8 dome.  The 3/8 means it is 3/8 of a sphere, so you can imagine just cutting the top 3/8 off a baseball, and that's what it will look like.  

Very informative. I like the way you talked about having all the "fun" during set up. Thank you.
Rather then tape. you could use a light nylon line and a Constrictor Knot on the rubber hose. <br> <br>http://en.wikipedia.org/wiki/Constrictor_knot <br> <br>great job fella
I'll pass this on to my brother, he was wanting to build his using some sort of lashing technique. Have you ever seen this in action on a dome? <br> <br>Thanks!
The Desert Domes site has a whole section on Bamboo Domes, put together using lashings. <br> <br>http://www.desertdomes.com/bamboo.html <br> <br>In this case a V3 dome is lashed using only two sets of 4 point vertices. Since all of your struts are components of your vertices, set up and construction consists entirely of preparing vertices and lashing those together to form struts already in place in your completed structure. <br> <br>The whole design and measurement system is set up to build from the top down, as opposed to a bottom-up construction, making it easier to place and attach your covering as you construct your dome.
That's exactly what my brother is doing, although he hasn't made much progress this summer. I helped him lash the first few together, and it was actually really easy and fast.
... and i quote; &quot;... Zip Ties are a wonderful thing. :)&quot;
I guess you don't get wind where your dome is!<br> <br> It should be anchored to the ground with either 3 foot long 2 x 2 stakes or rebar hooks or it will blow away.<br> <br> Tape is never going to be a satisfactory solution to securing a structure.<br> <br> Glue the rubber pipe onto the wood or put a small screw through the pipe on each - Amazingly a normal hand screw driver works just as well as the electric ones.<br> <br> see <a href="http://www.instructables.com/id/Geodetic-greenhouse-low-cost/" rel="nofollow">http://www.instructables.com/id/Geodetic-greenhouse-low-cost/</a>
Thanks for the comment. I've already replaced the tape with screws, it wouldn't have taken so long but my drill was on vacation. <br> <br>I have been considering the anchors. I'd like to make them removable, as it's a portable structure. You'll notice it's in two different spots in the pictures. It does get quite windy here, so I must prepare!
you can get &quot; dog leashes&quot; earth screws for cheap at china mart or pet store, this would hold your dome down.
Buck Minster Fuller himself noted that a large enough dome, one half mile by his estimate, would create enough heat on the interior via solar energy, to lift the entire structure off the ground, similar to a hot air balloon. <br> <br>For a simplistic, inexpensive, and rapidly mobile anchoring system, try attaching one gallon plastic bottles full of water to each of the vertices once removed from the ground, around the perimeter of your dome. Each of the bottles would weigh 8 to 9 pounds (1 gallon distilled water equals 8.4 pounds) and with enough string could hang one to 2 inches off the ground, providing an extra 120 pounds of Anchorage to your structure.
Yes, two or three iterations from now, mine will fly! Muahahahahhahahh!
I like that greenhouse! I have the same problem with the joints, they are a little floppy. When it's all together, they hold very well, but with a load pushing directly down on them, it inverts the hexagon or pentagon. This happens because neighboring vertices all slip and fudge around enough to give the one I'm pushing on enough room to flip inward. A backing, as in the instructable you linked to, may be able to take care of that.
Nice work. I built a 28' diameter 4/8 dome in 1975, using 2&quot; x 2&quot; stock. I milled the stock with an Alaskan brand chain saw mill from a Douglas fir log about 18&quot; in diameter. Made all of the vertices from 3/4 plywood which I got as scrap from a cabinet makers shop. Cutting them was tedious with a hand saw, then clipped the tips off to leave a 1.5 inch flat normal to the strut vectors. Each strut was cut for half-lap joints on the ends, and then wood screwed to the plywood vertices. My only power tool was the chain saw. Building the dome frame cost about $10, mostly in chain saw fuel and wood screws. <br> <br>I wanted a durable, cheap, insulated covering, so I covered it with the cheapest thing I could find - a surplus Army parachute, stapled to every strut with furring strips. Then I used a commercial spray rig (my Dad's company owned it) to cover it with about an inch of spay on foam insulation, covered that with 3/4&quot; mesh chicken wire, then another inch of foam. Let that cure a week, then painted it with asphalt mobile home roofing compound. It is still standing, on my brothers property, which frequently gets 18&quot; or more of snow in winter.
Wow that sounds like you're hitting a lot of the things I was hoping for on the next episode. How much did you spend on the chicken wire? Did you Dad say how much the foam would have cost if it wasn't in the family? Was it closed cell or open cell foam? How is the inside temperature during the winter? From my research the spray on foam seems like one of the quickest ways to take a dome from frame to complete. <br> <br>Thanks! <br> <br>
It was a long time ago, but as I recall the chicken wire was $18 for an 8' by 100' roll. I bought three rolls, so $54. If you know what &quot;hog rings&quot; are as used in upholstery, then you'll understand when I tell you that I used those to edge join the sections of chicken wire. The foam was closed cell polyurethane foam. My Dad owned the spray gun and mixer, I bought one barrel of each liquid component through his company, and spent $84 on them. I really don't remember the cost of the two 5 gallon buckets of asphalt roofing paint, or the rollers - it was pretty cheap. <br> <br>My brother repaints the dome every 5 years or so, and he also sprayed the interior with Kilz epoxy sealant paint, and installed two bi-metallic coil thermostatically opening vents at the peak - those are still available, made for greenhouses. It is quire warm inside, even when buried under snow. He has a &quot;dairy barn&quot; type small electric heater in it. <br> <br>I actually built 5 domes, in total, but only the one geodesic. The rest were experiments, and two of them failed pretty quickly. The other two stood up quite well, and one of them is still being used as originally installed - as the roof of a hay storage/stable which is 24' in diameter. We set that one on a frame that lifted the lower edge of the hemishere 8' feet in the air, while leaving the opposite edge 4&quot; off the ground on framing.
This one has actually failed now. I am going to post some pictures, and a write up, shortly. It wasn't the dome, or the materials fault, it was operator misuse. I picked it up (with two other guys,) and we moved it onto a slope, so I could use it to keep cows out of a garden area. The slope caused breakage, and a very long, slow process of destruction. I let it happen in order to see the results, and I'll post it as soon as my camera is rounded up.
I tried this in 1970. Blew away in the first high wind. Nothing of value could be salvaged. Hope you have better luck .
Yes, I still haven't figured out a good, movable tie down system. If I've got it attached well enough to not blow away, the way I think it might get destroyed is just by being flattened. We'll see! Thanks!
I had a thought. what about the tent weights used for art fair tents? assuming the structure can support that much weight, but it would not have to be very much per &quot;leg.&quot; http://keletica.com/keletica-dialectic/44-howto/70-weighty-subject.html
That would probably work very well.
So here is a question from someone with very little geo-dome experience, just this 'bile and some observations... <br> <br>At our local playground is a geo-dome play structure (old school style). what they did was take metal pipe and pinch the ends flat and put a bolt through the connections. ( they &quot;finished&quot; it with a large 4' washer on the outside). <br> <br>So why could you not just do the same thing with PVC? That is , heat the ends, pinch them in a vice and drill a hole. The only hitch would be the &quot;length&quot; in the dome calculator would be the distance between the holes. This can be done with a simple jig. this would address the rigidity issue, and simplify construction. <br> <br>Any thoughts?
I've had some friends back here that have been asking about PVC as well. I preer to avoid it because I've heard it's pretty toxic. Even if it isn't, when it breaks, then I've got a million little shards that are going to be laying around forever. But if one were to use it, a friends suggested that you could heat it up in order to bend the connectors to the required angles (which I believe are listed a couple comments below. <br> <br>The galvanized steel would make a super strong dome, but I didn't want to spend the money on it. My neighbor has some that we will be using to build him a dome though, so stand by for an instructable on that. <br> <br>Thanks for writing!
The ones that bent were, I think, 1-inch electrical conduit. Whatever that was in 1970, probably steel.
Electrical conduit makes some seriously strong domes. If I had a bunch extra of it sitting around, I'd use it. My next one will be with 2&quot; x 6&quot; 's, because it's going to be ginormous, and I have a lumber yard right up the road.
i don't know what this means.
The problem is not that they &quot;need to do some research of [their] own - and learn.&quot; The problem is that you posted a semi-coherent sentence with zero context. &nbsp;Let's break down the core of your post, which is pretty much just the one sentence...<br> <br> &quot;Some angle iron about 120 - 160mm over size,&quot;<br> Comma denotes a break. &nbsp;So let's look at this... Yeah, I know what angle iron is. &nbsp;What context you mean by &quot;120-160mm over size&quot; is anyone's guess. &nbsp;A Google for &quot;120-160mm over size angle iron&quot; isn't going to return anything helpful. &nbsp;By carefully pulling apart the sentence, I'm assuming you're saying the piece of angle iron is going to be the base of your jig and needs to be 120-160mm longer than the strut you're trying to make? &nbsp;But I can only guess here.<br> <br> &quot;3 holes - one to put a bolt into as the cutting stop, one as the locating pin, and on as the drilling location hole.&quot;<br> Where are the three holes going? &nbsp;The cutting stop for what? &nbsp;Sure you're making a &quot;universal cutting AND drilling jig&quot; but what are the bolts going into? &nbsp;The angle iron that's about 120-160mm over size? &nbsp;And what is the &quot;locating pin&quot;, and the &quot;drilling location hole&quot; locating? &nbsp;And for which drilling?<br> <br> Your sentence didn't make sense. &nbsp;Covo stated that. &nbsp;I'm stating that too. &nbsp;Getting snarky and saying, &quot;WELL GO DO SOME RESEARCH&quot; is not the appropriate response. &nbsp;I know you're good at being helpful when you want to be (I particularly liked your 'ible on using polyfill for a pool filter - will be doing that for my hottub once we get it running).<br> <br> I would honestly be interested in knowing what kind of jig you're talking about, and how you picture it should be constructed. &nbsp;I would actually like to build one of these domes as a greenhouse.
Be nice! We're all here to learn...
Not sure about PVC, but there have been people who have used galvanized electrical conduit. PVC seems to get a bit brittle over the years when exposed continuously to UV.
PVC isn't UV or temperature stable- 3 months in direct sun and it starts to disentergrate- CPVC (the grey kind) is better, but more expensive and more flexible- <br> <br>I built a lot of crazy stuff with PVC (google Sam's Nascar simulator) but nothing that will get a lot of sun---
I built one like this a few years ago using PVC pipe, black rubber hoses from some old washing machines and some cable ties (zip ties). The plastic cable ties work great for securing the struts to the hose connectors. Great job! <br />
Thanks! Zip ties are a wonderful thing :)
Yay! Ron Paul! ;-) <br> <br>(re: Ron Paul bumper sticker in pic.) <br>
Yeah, nice sticker! This one gets a vote-up for general intelligence! ;o)
Great, you must be believers in Liberty and the Bill of Rights!
Indeed sir! (and a dome-o-phile)
Pretty scary rounding the ends of the struts... Have you ever seen rotary tenon cutters like this? <br> <br>http://www.rockler.com/product.cfm?page=11459&amp;rrt=1
Yes, I did get bit once. Those cutters looks pretty great., but it's kind of expensive. At that price you're already a quarter of the way to a home fabricator, and printing out the vertices yourself. <br> <br>http://www.makergear.com/products/3d-printers <br> <br>Thanks for the comment!
I wanted to get one of those tenon cutters myself but the price of the cutter would've been more than all of the other materials put together. My solution: a 1 inch diameter hole saw with a 1/16th inch blade thickness. My vertices are simply six-inch round stock, sliced 1-1/2 inch thick, and drilled with a 7/8th inch speed boring bit. <br> <br>I use a hack saw with a carbide grit bar blade to cut away excess material from around the tenon, in a hex pattern. <br> <br>Total cost for the hole saw, speed boring bit, and hacksaw bar blade, about eight dollars.
Great job! I've always meant to build one. maybe this will get me started. seems like if you used pvc pipe that just fit into the hose, it would be a pretty quick job although a bit more money than scrap wood. <br>I was wondering if you could start assembly at the top. Ie build the top pentagon and then lift one side and add the next row etc.
Buckminster built a lot, if not all of his domes from the top down. They used some sort of jack or crane, like they use in grain elevator construction, and just had a crew of guys attaching a row, then jack it up one level, attach another row, etc. He built huge domes, 200' across, in a couple days using this method! I'm definitely in the market. <br> <br>I still don't like PVC too much, mainly because it's a permanent plastic, so we're going to try bamboo next. We've already got 6' pieces, which means if we built the exact same dome, it would be 28' across instead.
Thank you for the tips. After reading your Instructions I believe I could build this type of green house also. You got a vote from me. Thanks again.
Thank you! I'd love to know how it works out.
If anyone is interested the author mentioned duct tape not working to good. I'd like to recommend Permacel Pipe Wrap tape. I've stopped using duct tape when I really want something tough as nails. The strength and adhesion of this stuff is extraordinary, you can barely peel it off the roll. In the 6&quot; wide it helps to have two people unwinding it. I've never seen anyone tear it and you need a sharp blade to cut it. And it isn't coming off. It is thicker then any tape I've ever tried. <br> <br>No I don't represent the company. Oh and it isn't cheap.
Hmmm... I'd be interested to know if that would have permanently secured it. The other reason I'm losing the tape, though, is that it too SO MUCH TIME wrapping every connection. Cutting that part out of the labor will cut a day or more out of total time to completion. <br> <br>Thanks for the advice though, now I know where to go when I need super tape!
Thanks for the questions: <br> <br>It's untreated pine from my local lumber mill. I understand what you're saying, it's important to keep the food clean, and using a bunch of chemicals would defeat the purpose. <br> <br>The results have already been worthwhile, just with the lessons learned. If I get to watch it get demolished in the next wind storm, I feel it'll be worth that data as well. It's late enough in the season that I'm thinking of just throwing some chicken wire over it and using it to keep livestock off some of my trees though, which means the big wind storm tests won't come until September. By then we'll have some more built out of bamboo and fabricated vertices, so if I suffer a casualty I'll update this instructables with pictures, and advice to make them bigger than 3/4&quot;. I think that'll be worth it too.

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