The following list will build what I consider a single quonset module, defined by the top support, which is 10' long. My structures end up being 10' wide and multiples of 10' long (usually 20' total), but it can be extended as long as you want. A few questions to ask if you want to modify it:
Do I need more or less headroom or width? Less distance between arch anchor points makes a narrower, taller arch; more distance makes a wider, shorter arch.
Will my tent fit, both height and width? This is usually only a problem if you have a *big* dome or one of those cabin tent thingies. One option with cabin tents is to pitch the tent right against one of the quonset openings, which can help avoid a wind tunnel effect.
Materials list:
All PVC is schedule 40.
Don't use the thin wall stuff, or it *will* collapse!
7 pieces of 10' long, 1" diameter PVC pipe.
3 pieces of 7" long, 1 1/4" diameter PVC pipe.
6 pieces of 2' long, 1/2" or 3/4" diameter rebar.
3 pieces of 3' long, 2" wide innertube, or a big roll of duct
tape.
Drilling hammer or small sledgehammer.
Fabric to cover the frame (20' x 10' for full playa to playa coverage).
A bunch of 6" cable ties.
To add extra sections (per section):
5 pieces of 10' long, 1" diameter PVC pipe.
2 pieces of 7" long, 1 1/4" diameter PVC pipe.
4 pieces of 2' long, 1/2" or 3/4" diameter rebar.
2 pieces of 3' long, 2" wide innertube, or a big roll of duct
tape.
Fabric to cover the frame (20' x 10'/section for full playa to playa coverage).
A bunch of 6" cable ties.
Some of the materials used here are susceptible to UV deterioration, and the playa itself is very hard on some metals. PVC and cable ties both degrade in UV, and will become brittle over time. The week or so on the playa for Burning Man is not nearly enough time to affect them, though, so storage off the playa is the concern.
In my experience, PVC stored in a dry, shady spot holds up fine for years. I keep mine in the rafters in my garage (though it spends a few weeks outside each year), and have used a number of the pieces for many years running with no problems. If you leave them outside in the sun, you might risk them breaking under stress, though I've never seen a problem. I suppose you could wrap the PVC in the shade cloth and prop it up off the ground...