Developers often use steel to build the superstructures of skyscrapers, high-rise apartment buildings, bridges and other structures. Americans recycle more than 65 million tons of scrap steel each year. Recycled steel maintains its strength and durability. In fact, all steel framing contains at least 28 percent of recycled steel. To build a typical 2,000-square-foot house, workers will use an amount of steel equal to about six junked automobiles [source: Recycle Steel]. Steel girders, trusses and pilings can all be recycled from construction sites.