A waterbed or water mattress's a bed or mattress filled with water. Construction Waterbeds primarily consist of two types, hard-sided beds and soft-sided beds. A hard-sided waterbed consists of a water-containing mattress inside a rectangular frame of wood resting on a plywood deck that sits on a platform. Platforms may incorporate drawer systems for storage. Frames may be decorative, with elaborate headboards or tall posts. A soft-sided waterbed consists of a water-containing mattress inside of… (More on Waterbed)