Sound proofing the Dart

Peel & Seal is a cross-linked polymer modified rubberized asphalt. The flexible foil carrier allows less than <.01 permeability and if you tape seal the seams I can't see how anything could pass through it. It carries a class "A" fire rating. I bought mine at Lowes. It's available in widths from 3" to 36" although it's usually special order for anything other than the 6" or 36". Once you use the product I think you'll find it an excellent alternate. Dan