The pre-assembled structural insulated panels (SIPs) - polystyrene foam sandwiched between oriented strand boards for structural framing, insulation, and exterior sheathing needs- will increasingly outpace the conventional framings, reports greenbuildingelements.com. The oriented strand boards are made from wood of fast growing trees and emit very low levels of urea-formaldehyde. The polystyrene foam can also consist of recycled content. The use of SIPs provides increased energy efficiency, reduced wood usage, and less construction times. Besides, they can be as floors, walls, and roofs and provide much greater energy efficiency than insulation in stud walls improving the R-value by 15% to 40%.