I guess the big question is. Can it just be lying on the ground. Answer, No. As far as what the material is. I actually have a name for it on the tip of my tongue but it won't slide off. Again it is not protected in any way and needs to be changed. As far as the material just name any one of the approved materials but it still has to be protected no matter what it is. As far as the tape possibly "fixing a leak", well if it is it is obviously wrong. I wish I had better info for you but I am not where all my info is and I cannot pull it out of my hat.

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Ted Menelly
Castle Home Inspection Services
www.inspectmycastle.com