Abstract: Thermal insulated structures such as walls, ceilings and floors are produced for use in thermo-insulated cargo vans, box trucks, trailers, and other vehicles and compartments. A frame is built a frame in an area, and polyurethane foam insulation is sprayed onto the frame. The polyurethane foam insulation is cut, and then covered with polypropylene panels. The polypropylene panels are secured to the frame, and seams between the polypropylene panels are welded together. Plates are optionally secured to the edges of the panels.