This polymer tile mimics ½
-inch-thick natural slate with a rough edge. To achieve authentic color variations, the manufacturer bundles its shingles in as many as 11 different tones per pack. While only marginally cheaper than the real thing, the savings with synthetic slate is usually in the installation, which on average, can cost about 40 percent less.
Multi-width polymer "slate" in black, about $4.15 per square foot uninstalled; DaVinci Roofscapes