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Help me build a geodesic dome
August 12, 2012 3:31 PM   Subscribe

Tell me everything I need to know to build a standalone geodesic dome building, please.

I was watching a movie (The Go-Getter) and I saw a band practicing in a geodesic dome. I thought about it, and they must not be to terribly hard to build. All essentially the same size metal bars. I figured I would just need to learn to weld and then spend the time doing the labor of welding all of the pieces together, or am I over-simplifying things?

Any guides or pointers in the right direction would be greatly appreciated! Cheers!
posted by ejfox to Home & Garden (19 answers total) 10 users marked this as a favorite
I have helped construct several domes at Burning Man. you can get plans. the ones we used had 3 different lengths of bars (NOT all the same!!!)

we used conduit. one person cut them then hammered the ends flat and drilled holes (this part is pretty hard work).
each length had colored coded spray paint on ends and the diagram from which we worked was also color coded to minimize confusion/mistakes.

its one of those things that is really easy but has a bit of a learning curve. you want to build from the top down, lifting the dome to add each new layer, then you never need to climb the dome...but more people makes it a lot easier....then just lots of bolts, some elbow grease.

I don't know where my friends got their particular plans but I am sure there are many avail on the internets.

also I would not weld unless its really 100% permanent, you can bolt (as we did) and dome is completely dis- and re-mantle-able and highly transportable.
posted by supermedusa at 3:47 PM on August 12, 2012 [1 favorite]

Geodesic Dome Tent Construction Instructions are what supermedusa is talking about.
posted by zinon at 3:53 PM on August 12, 2012 [1 favorite]

Do you want just the playground-type thing with metal tubing or channel, or an actual building?
posted by olinerd at 4:01 PM on August 12, 2012

So just to be clear: First order geodesics are the only ones that have all the lengths the same size. They're the ones that'd be 20 sided if they were complete, so usually have 5 triangles overhead and 10 triangles around the side.

I've done those at Burning Man with 1½" and 2" 10' lengths of PVC, covered with military surplus parachutes. Corners drilled through and tied with rope. The 2" was after I figured out that there's a lot of wind stress in a big storm...

I've also helped build a few higher order domes out of conduit. In one case I spent a day crushing the ends of conduit with a sledge hammer, drilling holes, and giving them a slight bend. In the other case, we had the lengths all cut and marked, I think there were 3 different ones, and we clambered up the dome and bolted 'em in place while someone below hollered out "we need two with the yellow tape on those two connections".

I think we need a bit of a clarification: Are you thinking a basic first-order one, or something more complex, and as olinerd asked: Tubing, to be covered with fabric (old cargo parachutes are cheap at surplus stores), or a real building?
posted by straw at 4:04 PM on August 12, 2012

"...or am I over-simplifying things?"

Well, if you really want to over-simplify things, I would encourage you to take advantage of decades of research that have been done, and think instead about building a hexayurt. They are much, much easier (and cheaper) to build than a true geodesic dome, they look approximately similar, and they don't leak like a dome. Just a thought.
posted by seasparrow at 4:04 PM on August 12, 2012 [2 favorites]

Check out DomeBook 2, a wonderful book from 1971 now available free.
posted by Kerasia at 4:06 PM on August 12, 2012 [2 favorites]

Just to emphasize what seasparrow hinted at, geodesic domes really like to leak, even those built by professionals. That's no big deal for a weekend kids project (Kids love to build 'em out of PVC pipe and a tarp) or for a Burning Man structure. But if you're thinking of a permanent structure from scratch you're going to have trouble keeping the rain out. Most building materials are made for 90ยบ joints which are easy to make reliably, and the design of most buildings limit the number of outside joints. Geodesics have complex joints and there are tons and tons of them. They all need to be done correctly to keep water (and pests) out. If you want natural lighting it can be a pain as well. Non-square windows are expensive, and you can only put a tiny square pane in a triangular or hexagonal space.

This might not be a problem if you're looking to essentially build a funky garden shed.

Domes also feel like they have less space in them than a comparable rectangular building because of all the awkward concave wall space that's impossible to put anything flush against.
posted by Ookseer at 4:27 PM on August 12, 2012 [4 favorites]

Yeah, I came in to mention the leakage factor as well.
posted by Specklet at 4:32 PM on August 12, 2012

Geodesic domes are fascinating, but very difficult to do well. There are many, many designs and kits available online, but first you need to figure out exactly what your requirements are. Only then can you start filtering through all the variations and find a design which fits what you want.

As appealing as domes are, other shapes (typical "house" shape of box + two-sided roof) are much simpler, cheaper, easier, and more reliable to build. Usually you only build a dome because there is a specific feature of a dome that you need.

So...yes, you're over-simplifying things :) Start with your requirements, and find a form which fits your function.
posted by jpeacock at 4:37 PM on August 12, 2012

It's fairly straightforward to construct a permanent dome that doesn't leak (or at least not any worse than conventional stick framed buildings). A wide variety of membranes are available whose seams can be welded to effectively provide weather proofing of irregularly shaped roof structures. Or one can use sheet metal and automotive style adhesives. Or welded steel. Or even fibreglass. None of these thing will be as cheap as conventional shingles and of course they come with all their own limitations.

A calculator for figuring out angles and lengths. Sadly the lead link for this FPP is dead but there are lots of links in the discussion you might find useful.
posted by Mitheral at 5:28 PM on August 12, 2012 [1 favorite]

I slept in a giant tent once built by a guy. He used a bunch of broom handles with holes drilled in the ends, through which he used electrical ties to tie the joints together. He covered the whole thing with a cover for a large above ground pool. It wasn't a permanent structure, of course, but it was easy to put together and solid.
posted by bondcliff at 5:56 PM on August 12, 2012

They leak.
posted by OmieWise at 6:27 PM on August 12, 2012

On preview: I see that was covered. Still, it's worth saying.
posted by OmieWise at 6:27 PM on August 12, 2012

It's fairly straightforward to construct a permanent dome that doesn't leak

Which is not what a lot of people that have built them and lived in them say.
posted by wilful at 7:48 PM on August 12, 2012 [4 favorites]

I have scene a couple of domes on hgtv that do not leak. I am guessing non professional ones will probably leak. IF you are doing it to live or even as a shed I would find a professional company who specializes in it to build it.
posted by majortom1981 at 4:52 AM on August 13, 2012

They leak if your membrane (the wall/roof material) requires joints at bends, such as if you use wood or metal. They don't leak (more than other structures, and possibly less) if your membrane is continuous, like plastic sheeting, canvas, or mylar. The vast majority of geodesic homes are covered in rigid materials.

The Denver Airport, while not a geodesic, is covered in a fabric of some sort; thus, they are used for serious, permanent structures.

But if the membrane must be joined at each bend (edges of polygons, points of same), then the number of two-piece seams (edges) is huge per unit area. Each joint is an opportunity to fail; chance of failure = chance/foot of joint * feet of joint. Any roof has a chance of failing, but obviously one with many more seams has more.
posted by IAmBroom at 9:13 AM on August 13, 2012

i built a dome some years ago. it was more less a low dollar rave tent type thing built out of EMT conduit. I bought the plans from someone, don't remember who, but they faxed them to me :)

the tent construction link above is a good start, but i would search around for plans and exactly what size is going to fulfill your mission.

In addition to that I would add two things that made the fabrication work much easier, and make the results much more accurate.

1. borrow or buy a cheap arbor presslike this one from harbor freight. - use this to crimp the ends of your conduit. you can also use this to get your 12 degree bend in the end of each section after drilling.

2. The overall length of the conduit sections is not super-critical, +/- 1/4 inch is fine, however the hole-to-hole dimension NEEDS TO BE VERY ACCURATE. For this you should use a small drill press, and build a jig to make your hole dims accurate. Your jig will be a length of wood or steel tubing with a pin or small bolt on the end of it (smaller diameter than the fastener you will be using) you will put this jig in the vice on your drill press, and measure the center of your pin to the center of your drill bit and adjust til you have your exact measurement. you drill your first hole, flip the section over and put that hole on the pin. now the drill bit is located to maintain the exact distance.

3. you'll want a disc sander or similar to remove the nasty sharp edges from your conduit after its all done. this is important.

I did all operations over the span of two evenings in a machine shop by myself.

it will be a gigantic pain in the ass the first time you build your dome. it will take all day. after the 4th time or so you'll have it down to a few hours using a small crew. you'll also learn that it is easier to pre-fabricate the top section of the dome and lift / connect it in place on poles, as it is easier than hauling around huge step ladders.
posted by freq at 9:16 AM on August 13, 2012 [1 favorite]

Also, color-code each different length of section with spray paint on the ends! IIRC we had 4 or 5 different lengths to contend with. finding a small number written on a segment is way harder than looking at a pile of tubes that are all pink or green or yellow on the ends.
posted by freq at 9:35 AM on August 13, 2012 [1 favorite]

Just following up six months later to let you know I found a neat dome resource site called domerama with some pretty good information on hub connectors. Here is the obligatory Cool Tools review.
posted by seasparrow at 3:20 PM on December 27, 2012

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