Simpson Strong Tie C810RN1 8D Roofing Tile and Slating Nails, 2-1/2-Inch and 10-Gauge, Copper Smooth Shank 1-Pound, 81-Piece 7/16-inch head diameter and .134-inch shank diameter Large flat head provides extra bearing surface For Slate roofs determine the correct nail length by doubling the slate thickness and adding one inch Longer lengths ideal for installing curved Spanish roof tiles and thicker slate Aluminum nails also available with a screw shank