Step 1
Space the support boards properly. Because surface boards placed on an angle in a herringbone pattern have a longer span than boards placed straight across, they need additional support. The row spacing for 2-by-6-inch surface boards at a 45-degree angle is 22 inches on center, maximum. For composite decking, a maximum of 12 inches is adequate.
Step 2
Add additional blocking to support the boards. Place two 2-by-6-inch treated blocking boards between the 2-by-6-inch support boards at the locations where you want the herringbone pattern to occur. Leave a ½-inch space between the blocking boards.
Step 3
Make a plywood triangle and place it in a corner of the deck to set the angle for the boards. Lay the surface boards in a diagonal herringbone pattern at a 45-degree angle. Measure carefully and make sure that all cuts to the interior of the deck are square and aligned equally along the blocking boards. Allow the boards to overhang the edge of the deck. Secure the decking and trim all the edges of the boards at the same time.