The idea of building our own shelter fascinates us, but for the average handyman, where do you start?
A geodesic dome made of PVC may be the most cost-effective method of building a structurally solid yet transportable shelter, and it’s possible to build one in a single day.
At Maker Faire 2014 in New York City, the Sketchup team did just that. Why? We wanted something that was easy and fun to assemble, but it also needed to be impressive, yet duplicable by anyone with just basic tools. While this structure may look daunting to build, you could actually do it in your garage on a Saturday afternoon.
We’ll show you how we built ours, and how you can use Sketchup to easily design and build your own, of any size.
To begin, you can see our Maker Faire domes in action here and in the video below
The History of the Geodesic Dome
Let’s get something out of the way: our team didn’t invent geodomes; Buckminster “Bucky” Fuller did. Let’s learn a little about him, courtesy of the Bucky Fuller Institute.
R. Buckminster Fuller was a renowned 20th century inventor and visionary born in Milton, Massachusetts on July 12, 1895. Dedicating his life to making the world work for all of humanity, Fuller operated as a practical philosopher who demonstrated his ideas as inventions that he called “artifacts.”
Fuller did not limit himself to one field but worked as a ‘comprehensive anticipatory design scientist’ to solve global problems surrounding housing, shelter, transportation, education, energy, ecological destruction, and poverty. Throughout the course of his life, Fuller held 28 patents, authored 28 books, and received 47 honorary degrees. And while his most well known artifact, the geodesic dome, has been produced over 300,000 times worldwide, Fuller’s true impact on the world today can be found in his continued influence upon generations of designers, architects, scientists and artists working to create a more sustainable planet.
The Different Types of Geodesic Domes
Geodesic domes can be exceedingly detailed or incredibly simple. The varying levels of detail are called “tessellations” The more tessellations you have, the smoother your dome is.
Some of the more commonly built domes are 3V to 6V domes. A 3V dome has three different strut lengths—as you go up in detail, you decrease the strut length, and increase the number of struts. The smoother your dome is, the more hubs and struts you need. These images below (from SonostarHub.com) show a map of what half of a dome looks like in each tessellation.
Your first decision to make is the size of your dome. At Maker Faire, we were limited to a confined space that we were allowed to use.
SketchUp can help you visualize things like this very easily. For that, you’d want to draw out your dome to see how it would fit. To quickly resize the dome, we built a Dynamic Component. These types of components can be programmed to redraw themselves. We set ours up so that we could type in different diameters of domes. Our component automatically calculates how much pipe you will need for whatever size and detail of dome you choose.
You can download a model of our dome to use within the free Sketchup software.
Once you have the model downloaded, right click on it (or secondary click if you’re on a Mac) and select “Dynamic Components” and then “Options.”
You will be presented with a menu that looks like the image below. There, you can change the diameter of the dome. Press “Apply” at the bottom and your dome will automatically rebuild itself to the size you want. You’ll get a parts list, as well (more on the parts list later).
We used this model to place our domes on the site. After much discussion, we decided on the dual 20′ dome setup you see below:
You can download our as-built model if you want to check it out in SketchUp.
Putting Together Your Materials List
Geodesic domes can be made out of all sorts of materials, from a stack of toothpicks on your desk to a big metal building. No matter what you make your dome out of, you need to calculate the amount of hubs you need, and the length of all of your struts.
You want to make sure that you get this right, because the cost of a mistake would mean a very expensive pile of PVC that would quickly become useless.
Indulge me while I quickly explain the theory behind the different ways you can calculate struts, and then I’ll point you to some good calculators.
This article from Berkley explains, in great detail, the math behind these domes. The formulae show you how to calculate a wire mesh dome. In other words, these math formulas will tell you the total distance of each strut.
This is a good starting point, but if you’re making or buying your own hubs, you’ll need to subtract for their length where they connect.
If you know the amount you need to subtract for each hub, you can put that into our Dynamic Component above. In the case of the hubs we used from SonoStarHub.com, they have their own calculator on their site that works fantastic.
Getting the Right Hubs
Hubs connect all of the struts together to form the structure. These aren’t something you can get off the shelf at your local hardware store. We explored ways to fabricate our own (there are many) but we ultimately went with a company called SonoStarHub.com for our hubs. It saved time, and guaranteed safety in our exhibit. Sonostar makes and sells the hubs, bolts, and complete kits if you want them.
The hubs we chose are designed to work with 1.5″ Schedule 40 PVC pipe. This is off the shelf stuff that can be sourced from any Home Depot. The size refers to the inside diameter. Our pipe was actually 1.9″ in its outer diameter. Take a look at Home Depot’s selection of PVC pipes to start your supply list.
For our dome, we used 15 base hubs (these have 4 ‘arms’ on them), 6 5-star hubs, and 55 6-star hubs.
Now that we’ve planned our dome size and we know how many pipes and the lengths we need to cut, it’s time to start fabricating. After heading to Home Depot and watching the jaws drop at the pro desk after I asked for over 150 10′ PVC pipes, I had to come up with a way to cut tons of pipe at exactly the same length.
Normally, I use my chop saw and I mark off lengths of things to cut, but that would be inefficient for this amount of pipes. For this task, I used a chop saw stand with stops on it. This way, I could set the length and repeat cuts over and over again. Make sure that when you get one that it has very sturdy stops on it.
The first stand I bought did not, and I had to return it in favor of one that wasn’t moving when I bumped it a little. Once you have this setup, measure from the saw blade to the stop and start cutting.
Now that you have a massive pile of pipes cut up (the image above is only for one dome), you’ll need to drill holes in each end so that you can bolt them to the hubs when you’re on site. The holes need to be lined up on each end.
To do that, I put the pipe against the stop, drilled the first hole, and then flipped the pipe over. Using the screw on the left, I was able to line up the first hole vertically so I could drill the second one.
Building Your Domes
Now you’ve got a huge pile of pipes, cut and labeled. This is where the fun begins! Let’s put this thing together.
Before we built both domes at Maker Faire, I built one with a helper on her front lawn just to make sure it worked. The two of us were able to build a 20′ dome in just a few hours, using a step ladder.
Below I’ll give you a solid overview of how we assembled it. For super detailed instructions, there is a download link at the end of this post that includes all the detailed build instructions, and all the models you’ll need in order to assemble what we built.
The first step is to lay out the base ring of pipes and bolt each connection together, using the 4-armed hubs. Don’t worry if the ground isn’t perfectly level. If there is a big drop off, just slide a chunk of wood or spare pipe underneath to jack the dome up (for now).
After laying out the base ring, start making pentagons. There will be 6 total. Fully assemble and bolt them together, and then set them aside.
Next, put the first round of base poles up, adding a 6-star hub every third set.
Now it’s time to start adding pentagons. Connect them with the remainder of the red pipes, and use the blue cross pipes to connect them together. Don’t forget to bolt as you go!
Keep filling in pipes around the pentagons.
Add the last pentagon at the very top, and savor the moment!
Now that you have the dome fully built, you can remove a section of 6-spoked (red) poles to create a door. If you need to move or turn the dome, it’s light enough that about six people can lift and easily move it.
That’s how you build and fabricate a PVC Geodesic Dome!
These are incredibly strong structures that are fun and rewarding to build. Here are the full instructions, including a printable assembly document, 3D models, pictures and video.
If you think you can do a better job than me, you’re welcome to contribute any work on GitHub.