IB-3 IceBuster is a self-adhering, 50 mil mineral surface waterproof underlayment for use under shingles, tile and other types of roofing. It is constructed from a strong layer of mesh bonded to rubberized asphalt and coated with black stone granules. It prevents leaks due to ice dams and blowing rain. Use in valleys, around exterior penetrations and along the roof edge for waterproofing protection. No selvedge edge. Packaged one roll per carton. 5-Year Warranty.