Timber Products. The company’s softwood plywood comes in 8-, 9-, and 10-foot lengths; 4- and 5-foot widths; and thicknesses from 5/16 inch to 2 inches. It is available in several grades for sheathing, concrete forms, and underlayment. The panels are SFI-certified and are available with FSC certification. 800.547.9520. www.timberproducts.com.