The names often get swapped out for each other. Insulated metal panels, or IMPs, are frequently referred to as sandwich panels due to their structure: a layer of foam insulation nestled between two metal sheets. These panels serve as the outer walls and roofs of buildings and consist of a solid layer of insulation sandwiched between two sheets of metal, typically aluminum or steel. The insulating material is injected between these metal sheets and then cut to the required lengths.