The ground cover is mill felt. It's used in the paper machines. If you know someone who works in a paper mill you can usually get your hands on some. I was lucky enough to get a large piece. About 20 feet wide and 200 feet long, it works great as ground cover or as walls for a pole barn. I live in a mill town and you see it everywhere! Thanks for the comments on the website, I am not very computer savvy and I managed to build it myself.