A.Jay Meunier, contracting specialist at S.T. Griswold and Co., a ready-mixed concrete supplier in Williston, Vt., responds: First, check with your local building authorities to find out what local codes apply.

I have never seen architectural or structural drawings that did not indicate some amount of reinforcing for concrete piers. We usually recommend that a minimum of two pieces of #4 rebar be placed vertically in an 8-inch-diameter concrete pier supporting a structure. A larger-diameter pier should have four or more pieces of vertical rebar. The rebar provides the tensile strength needed to resist lateral stresses that can be applied to a concrete pier by ground movement, freeze cycles, and wind loads.