PRODUCT GUIDE Structural Steel Myzeil Shopping Mall, Frankfurt, Germany. Knippers Helbig. License: CC BY-SA 3.0. Behind the recommendations Related articles Behind the recommendations Related articles Structural Steel Products with high recycled content, reduced material use, or designed to help minimize thermal bridging. More about Structural Steel Steel or Wood Framing: Which Way Should We Go? Volatile wood prices, declining quality of framing lumber, and environmental concerns have led many builders to consider alternatives to wood. Update on the Thermal Performance of Steel Framing Recycled Content in Steel Steel is made in two different facility types, which have different methods of producing and using recycled content in steel.