Download PDF version (224.7k) Log In or Register to view the full article as a PDF document.
Preventing Posts From Heaving To the Editor: There are several concepts in the answer about pergola posts (On the House, 2/02) that need some work. First, it is a myth that frost doesn’t grip and act on smooth surfaces. When Sonotubes first became popular, this was a common misconception. Every year I replace Sonotube footings that have heaved and turned over. The only way to prevent uplift with Sonotube piers is to add a flared footing at the bottom (below frost) and to add hooked bars from the footing up into the Sonotube form. Without the bars, frost will indeed snap off and lift the pier. Without hooks on the bottom, frost will actually draw the bars right out of