The deck post must be fastened to the concrete pier. It’s best to place a long 1/2-inch anchor bolt in the wet concrete that will be used to bolt down a heavy galvanized metal deck post base.

Figure concrete volume by multiplying the height of the post and column in feet by the radius of the tube in feet squared times 3.14. Divide the total by 27 to get the cubic yardage you need to order.