Jeff Higdon wrote:
However, I got sprayed with some water that was in one of those tanks and it gave me a mild chemical burn. That got me to thinking: Do I really want to live with those chemicals in my house for the next 50 years?
After looking online, I came up with www.repurposedmaterialsinc.com. They sell 45 mil rubber roofing for $400 for about 2000 square feet.
The only problem is the holes and irregular shapes. I went and talked to a roofing contractor who installs it, and he told me of a tape you can buy to seam it, though I have not sourced that yet.
They also sell billboard vinyls which could be used for many applications.