The present disclosure relates to an air handling system including a casing structure formed from a cohesive sheet of material. The air handling system also includes a first side wall of the casing structure including a first section of the cohesive sheet of material. The air handling system also includes a first support portion extending inwardly from the first side wall. The first support portion includes a folded portion of the first side wall. The air handling system also includes a second side wall disposed substantially opposite the first side wall. The second side wall includes a second section of the cohesive sheet of material. The air handling system further includes a second support portion extending inwardly from the second side wall. The second support portion includes a folded portion of the second side wall. The first and second support portions are configured to support a filter.