I need to line a 4x4x6 shed with reflective material. I see many cabinets that have a reflective material that has a cardboard looking backing, and is in large sheets.
A lot of people tape mylar to cardboard to get what they want, some people use windshield heat shields for their grow, i personally think mylar is the best for any grow
you can go to home depot and in or around the insulation area of the store.. they have these sheets that come bout the size of a sheet of drywall.. but the one side is the reflective material and works pretty well. used it on our room. take a peek if u'd like.