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How to Build a Geodesic Dome

Step by Step Instructions on Building a Geodesic Dome Using Sonostar Hardcore Geohubs


Use the dome calculator to determine the correct length of the different size struts. If you're using Sonostar standard or Megahubs, you'll need to use our Sonostar's Geodesic Dome Calculator that automatically deducts the width of the hubs from the strut lengths.


Standard Dome Calculator

Megadome Calculator



The hubs were designed to be used with Schedule 40 PVC. This can be found at almost any hardware or irrigation supply store. Remember that 1/2" pipe refers to the inside diameter of the pipe and not the outside diameter which is actually about .84". That's important because that's the diameter the hubs are made for. For our metric friends, the .84" would refer to 21 mm, which is the outside diameter of the pipe you want to put into the standard hubs.  


If you use our Megahubs, there are two build options:

1) If you insert the pipe into the hub arms, you’re looking for 1" PVC pipe which has an outside diameter of 1.315". Why? Because PVC pipe measurements are based on the airflow or water flow through the pipe, so the inside diameter is what the store is measuring. 

2) If you choose to use 1 1/2" pipe to go around the hub arms (this will provide the strongest structure possible), you'll need PVC pipe that has an inside diameter of 1 1/2", which is exactly what the store will sell you if you ask for 1 1/2" PVC pipe. The metric equivalents for our Megahubs are 31mm for the inside diameter and 38 mm for the outside diameter.


If you bought the Basic Kit, cut all your struts before you begin. Use a PVC cutting tool to cut the pipe, or set up a cutoff saw. You can also use a Skilsaw with a fine-tooth blade, or a hack saw.

PVC Cutting Tool


Color code all your struts with a stripe of colored electrical tape about 6” from either end. Follow the laminated color-coded map we include in each kit. Lay all your parts out beforehand and make a final count.


If you're gluing you dome together, be sure to have enough PVC primer and welding glue on hand to do the job. Nothing worse than getting to the end and discovering you're out of glue. Next, apply the primer to all your dome struts prior to beginning. Then apply the PVC cement to either the struts or the hubs, or both.

Gluing your PVC struts


If you're using nuts & bolts, refer to the info sheet titled "Building a Sonostar Geodome using Nuts and Bolts". There's a lot of useful information there.

 Building a 6V Geodesic Dome

Some Additional Helpful Tips

  • If your radius is more than 8’, be sure to have a ladder on hand.
  • Build your geodesic dome on a flat surface, if possible. Start from the ground up, putting together all the perimeter pieces first.
  • Make sure the curvature of the ground pieces is correct, with all the Geohubs oriented in/out
  • Push the struts all the way into the Dome Connectors. Use a hard rubber mallet if available) to bump the struts to the end of the hubs.
  • Mark your door location with an “X” on the struts that will be taken out (for the door), and then don’t glue them into the hubs. Once you get to the upper layers, you can remove them so you can go in and out.
  • Lay out one row in advance and have someone else double check the color coding using the map guide. If you are going to use glue, the welding cement sets up almost immediately, and you don’t want to mess up.
  • Designate someone to be the photographer. It's fun to take pictures at every stage of building. Better yet, set up your cell phone with the time lapse function and it will record a video for you.
  • PVC can get brittle when exposed to prolonged UV rays (like anywhere outside) A coat of spray paint will protect the pipes and the hubs.

***If you’re building a Frequency 6 dome, don’t confuse blue and turquoise, or red and pink length struts. When you print out the map diagram, some printers make the colors look very similar. Always check the letter codes for those colors, too.


Have fun. Marvel at the genius who figured out all the geometry. Tell your friends what you’re doing, and let them help – it’s a lot more fun with more people helping.