By providing arms and lending support to seat bottoms and backs, risers turn bleachers into auditorium seating. Cast iron can take on ornate decorative patterns, something to keep in mind if your installation is a historic one. Formed steel is a less expensive option and, if you are installing it indoors, a good bet, according to Wood. Out in the elements, however, formed steel can rust. But, over time, cars rust, too.
Cast aluminum represents the newest riser option of the three.
As it doesn't corrode or break, the material is perfectly suited to all outdoor situations. Colors and decorative options abound, so choosing an attractive riser is easy. The material is quite light, making transportation fairly inexpensive, but cast aluminum risers are usually the more expensive choice. Padding and marine vinyl or other weather-resistant fabric add both comfort and cost. If television cameras will be present, like for a football game, consider how the seats will look from a distance.