How thick is a wall for a semi trailer?

The walls of a standard semi-trailer typically range from about 1.5 inches to 3 inches in thickness, depending on the type of trailer and its intended use. For example, dry freight trailers often have walls around 1.5 to 2 inches thick, while refrigerated trailers may have thicker walls, around 3 inches, to provide better insulation. The specific thickness can vary based on the manufacturer and the materials used.