Geodome on the Big Island

How to build a GeoDome

Building a huge dome in your back yard is easier than you think. Yes, there is a bit of math but nothing a 10 year old could not figure out. And hey, if you get stuck, I love talking to people about this sort of thing. Email me at evanknight@gmail.com and I would be happy to point you in the right directions.

LET’S GET STARTED

COST $750 USD. Surprisingly cheap…we built the huge one for about $750 USD worth of material. I’m sure if you hunted around a bit or made it smaller you could even get it for less than that.

MATERIALS

Some people make these out of metal, but I’m a wood worker so I made it out of 2x2 material. You are going to need:

70 2x2x8, 10 2x4x8, 1 4x4x8, Really good glue, 70 Huge screws, 20 1.5 inch screws, 40 3 inch screws, 10 cement blocks, 10 L brackets, 20 Cement Screws

TOOLS : Saw, drill caulk gun, tape measure

OPTIONAL TOOLS TO MAKE YOUR LIFE EASIER: Chop Saw that can do 16 degree and 18 degree cuts, Impact Driver (Drill that pushes in a bit more), Pocket hole jig

HOW TO CUT YOUR MATERIALS (FOR A 25 FT DOME) (Note: works way better if you align the grain on all the lumber for the screws to hold better)

PRE PAINT ALL YOUR MATERIALS : It’s a pretty high structure in the end, painting the boards on the ground might be way easier

CUT YOUR 2X2S INTO YOUR “STICKS” : Cut 35 2x2s to 94 inches with an inside angle of 18 degrees, Cut 30 2x2s to 83.25 inches with an inside angle of 15.86 degrees (16 seems to work fine), Pocket hole each stick, both sides, on the long side of the 2x2

CUT THE HUBS : Cut 6 Pentagon Hubs out of 4x4s about 3 inches thick, Cut 10 Hexagon Hubs out of 4x4s about 3 inches thick, Cut 10 Hexagon Feet (a hexagon with the bottom two edges cut off for a flat bottom) out of 4x4s about 3 inches thick, Predrill all sides of the hubs for the screws to go in

LEAVE THE LEGS : Chances are your terrain may not be perfectly even so just leave the legs at 8ft until you get your structure built

CUT YOUR ANGLE BRACES : Cut your angle braces at 23inches, 45 degree angles. One of the 45 degree angles will need an additional 18 degree angle to account for the curve of the bottom of the dome. You will need 10 of each, left and right. Predrill your angle braces for easy install

HOW TO ASSEMBLE Quick and Easy rule: Pentagon Hubs always connect to a short stick not the long stick. Hexagons hubs can connect to either Long or short.

Connect one pentagon hub to 5 short sticks. At the bottom of those 5 sticks attach 5 Hexagon Hubs. Connect all 5 Hexagon Hubs with Long sticks (Hexagon to Hexagon is always a long stick). Connect 2 long sticks to each hexagon painting diagonally to the ground. Do not put long stick on the hubs that face the ground. Add a Hexagon Hub at the bottom of those two long sticks. (while this is being built you will need to support the structure so that it’s own weight does not crack the hubs. The easiest way would be to get 10 friends to help. Attach a short stick to the Hexagons that are facing down. Attach a Pentagon hub to the facing down short stick. Attach Short sticks from the pentagon hubs to their Hexagon Neighbor hubs. Take a breakc it should be free standing at this point. In a clock wise or counter clock wise manner prop up each side with shorts attached to the pentagons and longs attached to the hexagons. All boards parallel to the ground should be long. Lift up the dome and make it pretty level, attach the legs. You may need to trim your legs to the desired height and to match up with the terrain you have placed it on. Install your angle braces left and right. Secure your legs to the cement blocks with cement screws into the blocks and deck screws into the legs

Caulk, seal and paint everything

RESOURCES This website has great calculators: http://www.domerama.com/calculators/2v-geodesic-dome-calculator/