The Retrofit MBI System is a patented clip and pin system for use with rFOIL’s insulation—a single or double layer of polyethylene bubbles bonded to and sandwiched between a highly reflective surface and a white polyethylene sheet—to insulate all types of metal buildings. The MBI Retrofit clip is installed to the bottom of the exposed roof purlins and inside the wall girts. The system allows for the addition of insulation mass. The Retrofit MBI System is lightweight, easy to handle and install. With its unique attachment system, in can be quickly installed with minimal interruption to the facility’s operation.