GAF Materials Corp. introduces new and improved Slateline® shingles. Slateline is a fiberglass-asphalt shingle that replicates the look of real slate at a fraction of the cost. Now with a modified design that includes a double row of specially formulated Dura Grip Adhesive, the new Slateline shingle carries a 110-mph limited wind warranty for the first 10 years. The shingles provide a stately appearance, with their patented extra-large 17- by 40-inch size.