A corner piece is provided for forming packaging elements. The corner piece includes an inner member and an outer member having respective apexes. A connecting member connects the inner and outer members and substantially aligns their apexes, while spacing the inner and outer members apart from one another. A securing element is provided in the outer member for securing an exterior edge protector along the outer member. The securing element includes substantially U-shaped retaining walls engageable with the exterior edge protector. In some embodiments, the spacing between the inner and outer members defines retaining cavities for securing adjacent sidewalls of a storage container.