The base is made from 1/4" luan plywood. You just need to have something solid to attach it to. If there are metal roof braces to screw it to, you are good to go. If not, you need to fabricate braces that run from side to side. The braces are made from 3/4" hardwood plywood, should have a slight curve to them to match the roof line, and do not touch the metal of the roof. You can attach the braces at the ends with some of the new epoxies, or I have used metal "T" straps with the "T" part screwed to the areas above the doors. I then make a grid by running more braces front to back. If you do this right, you can hang from the grid. You use hardwood plywood to prevent warping. I then use 1/8" PVC foamboard to glue whatever fabric, padding, and design that is needed.
No one lives forever, the trick is creating something that will.