A continuous process for preparing insulation panels having thick (0.2 mm to 1 mm) metal facing panels and a fiber-reinforced polymer foam core is disclosed. In the process, a bottom metal facing panel is continuously supplied. A mat of reinforcing fibers and a foamable resin composition are applied to the bottom facing panel. A flexible barrier layer is applied atop the foamable resin composition, and the assembly is passed through nip rolls to compress the assembly and force the resin composition into the fiber mat. An adhesive layer and top metallic facing layer are then applied on top of the flexible barrier layer, and the resulting assembly is gauged and cured by passing it through a double band laminator.