A cargo body includes sidewalls constructed of pairs of panels secured together at respective joints. Each panel is an assembled panel having a core, an interior skin, and an exterior skin. In some cases, each joint is formed to include overlapping edge portions of first and second ones of the adjacent pair of panels. Each of the overlapping edge portions has a thickness less than 20 percent of a total panel thickness of the corresponding one of the adjacent pair of panels such that the joint formed thereby defines a recess between co-facing edge portions of the first and second ones of the adjacent pair of panels. A profile insert defining a longitudinal channel is positioned in the recess defined by the overlapping edge portions at each joint. Each joint is secured by fixedly attaching the profile insert to the overlapping edge portions.