Abstract: In one embodiment, a frame assembly includes at least two frame members, each frame member comprising two mitered ends and defining an interior space divided into at least three longitudinal cavities, wherein one of the at least three cavities is a corner key cavity. The frame assembly further includes at least one corner key, wherein each half of each corner key is configured to fit into one end of one of the corner key cavities to form a corner. When the at least two frame members are joined using the corner key, the corner key cavity is adjacent to the outer perimeter of the frame assembly system. The outer perimeter of the frame assembly includes a contact portion configured to contact another frame assembly or a structure, wherein the corner key cavity extends across at least 90% of the contact portion of the outer perimeter of the frame assembly.