STYROFOAM Brand Buoyancy Billets Insulation are the smart choice for floating structures. Since the floating billets cannot become punctured or water-logged and do not corrode or break down into small particles, they can last a very long time. Billets are lightweight and easy to install, so building a dock, raft or boat house is a snap. Extremely Buoyant. It takes only one cubic foot of STYROFOAM brand buoyancy billets to float 55 pounds. Rugged: billets won't lose their buoyancy, even if punctured. Durable: They do not waterlog or corrode.