The hot-dip galvanized steel structure of a Rubb building generally takes the form of a series of lattice tubular or box section steel frames at 3 to 7 metre centres. Tubular purlins span between each of the frames and provide the necessary support for the cladding. Each frame is composed of smaller more manageable sections, which bolt together on site. Buildings spanning up to 100m are available in any length.
The steel framework is protected from corrosion by hot dip galvanizing. Galvanizing is the process of metallurgically bonding a tough coating of zinc into the steel surface. Microscopic analysis shows that there is no demarcation line between the steel and zinc but a gradual transition through a series of zinc-iron alloys. The protected coating is fused into the metal and therefore will give much better protection than other coatings such as paint. Whereas protection by paint may have to be re-processed every 5 or 6 years, protection by galvanizing should last in excess of 30 years, even in exterior usage in coastal environments.