There is a product sold at hardware stores called USeal. It's instant waterproof repair tape for roof flashing. I read somewhere about somebody using it in their car for sound dampening and it only cost about $13 for 12.5sq. ft. so I gave it a try and it works great. I've used the name brand stuff before and I really think this stuff works just as good. Or maybe I just put it on thicker because it was so much cheaper. Either way I don't think I've seen this product listed on this forum and it's worth mentioning. Same results at a less expensive price works for me.