I've got my tegu in a 6'x3'x3' enclosure in my room (it's a neodesha sitting directly on the ground) and I want to add a 7'x6' pen directly in front of it, then leave the cage glass open so he can go between the pen and enclosure as he pleases. The only problem is that the pen would be on carpet and although he usually defecates in his water bowl, I don't want him having an accident on the floor. Is there any kind of waterproof (and rip-resistant) cloth or bedding I could lay over my carpet? Any other ideas on construction?