FALK provides Galvalume coated steel for both the exterior and interior faces of its panels, available in thicknesses of 22, 24, and 26 gauge. Roofing typically uses at least 24 gauge for the exterior and 26 gauge for the interior. Customers can customize the thickness combination to suit their specific project requirements. For the best results, FALK recommends consulting with a structural engineer or design professional to determine the optimal steel thickness for your project.