Home Gardening How to build an Outdoor Storage Box on casters- step by step tutorial. Materials: (1) 4×8 sheet of quality pine plywood (6) 2×1-8 pre-primed trim board (1) 5/8 x8 PVC quarter round trim (2) 3.5 galvanized utility hinges (2) 2.5 rubber wheel swivel casters (2) 2.5 rubber wheel swivel casters with locks