Why Jackson County Deck Footings Have to Go Below the Frost Line

Water in the soil around a footing expands when it freezes, and the Kansas City area sees enough freeze-thaw cycling most winters that a shallow footing gets pushed and shifted year after year. A footing poured above the regional frost line, roughly 30 to 36 inches deep, is exactly why so many of the deck repairs we get called out for in Jackson County trace back to the footing rather than the boards themselves. A deck built to spec in a warmer state isn't automatically safe to replicate here — frost depth is regional, not universal.