Place wooden pallets or boards on the floor of the storage unit. Place a plastic drop cloth on top of the wooden pallets or boards. This will protect the sofa from being damaged in case of the flooding that can occur at storage facilities.
Put the sofa, upright, directly on top of the wooden pallets or boards. Do not place the sofa on its end; this position can stress the sofa's frame.
Cover the sofa with a canvas or cotton drop cloth to reduce dust buildup on the furniture; avoid storing anything near it that could possibly transfer dye or color.