The art of wood tank building goes back to the fifteenth century. People built barrels and tanks to hold liquids. We build hot tubs the same way medieval craftsmen built their tanks and barrels. Barrels, wooden tanks, and hot tubs are built from curved pieces of wood called staves. Craftsmen assemble the staves and place metal hoops around them to hold the staves in place. At Great Northern®, we make hot tubs out of redwood or cedar. We coat our hoops with plastic to eliminate rust. Back in the 60s hot tubs were made out of old wine vats or 500-gallon water tanks. The tub becomes watertight when the wood saturates, swells, and seals. Wooden vessels have always been popular with people who love depth and leg room. All-wood tubs are no longer as popular as they once were since all-wood construction requires clean, knot free heartwood from old growth trees. Who wants to sacrifice beautiful old trees to make hot tubs? You can get the benefits of a traditional all-wood tub (leg room, depth, and portability) with a modern, plastic lined tub. The best known lined tub is the Rubadub Tub®. Great Northern® Hot Tubs, a pioneer of the hot tub and spa industry, created it in 1978. These tubs are easy to clean and have the same hydrotherapy jets and equipment as spas.