Exterior, House Building Type, Cabin Building Type, Prefab Building Type, and Gable RoofLine Each prefabricated unit is covered in aluminum but built from SIPS: Structurally Insulated Panels that consist of thick insulation sandwiched between plywood panels. These high-performance panels keep the interior protected from the desert's ambient heat.  Modern, Off-the-Grid Homes by Aileen Kwun