Thanks guys!
remo, the walls are made out of insulation foam. Weve got some that are 2" thick and some 1 1/2". The ones that are 1 1/2" are actually 1/2" pieces stacked and taped together. We worked with what we had to keep cost down.
All the foam is wrapped in red duct tape, and taped down to the carpet with double sided heavy duty carpet tape.
They dont hold down for ever, but our shop is really dusty. In a clean area, I bet it would last years wihtout replacing. Ours has been up for 8 months and still goes strong. Weve only had to replace a few pieces of the double sided tape, and have doubled up the duct tape in some of the corners due to major amounts of impacts. There really isnt any damage, but front lips and canards dig into the tape a little.