Our Residential docks consist of a modular 12" box truss angle iron substructure, hot dipped galvanized after fabrication. All frames are bolted together using 1/2" galvanized bolts. The superstructure consist of 2 1/2" galvanized square tubing and 8"galvanized Z purlins. All encapsulated  floation meets or exceeds Corps. of Engineers specifications and is bolted to substructure using galvanized fasteners.