StruStructural insulated panels (or structural insulating panels), SIPs, are a composite building material. They consist of a sandwich of two layers of structural board with an insulating layer of foam in between. The board is usually oriented strand board (OSB) and the foam either expanded polystyrene foam (EPS), extruded polystyrene foam (XPS) or polyurethane foam.
Above sketch shows the standard sandwich panels for wall and on the right side is the way to join panels.
Above sketch shows the standard sandwich panesl for roof and on the right side is the way to join panels, Please also check the following sketch for how to fix the panels on roof.
Some project samples build with sandwich panels for your reference.