Pre-Engineered Steel buildings (PEMBs) are structures made from prefabricated parts that are assembled on site. PEMBs are made up of three main parts: the primary framing (which includes the roof panels and wall panels), the secondary framing (which supports the primary framing), and the metal cladding (which covers the outside of the building). The primary framing is usually made out of steel, while the secondary framing and cladding can be made out of either steel or aluminum.