01
Require traceable documents
Product data should identify source, product, size, thickness range, weathering behavior, tests, fasteners and accessory materials. Samples should represent normal production.
02
Build a meaningful mockup
Include enough courses to show headlap, joints, thickness sorting and the intended appearance. Add a representative eave, valley, wall or ridge detail where it is central to the project.
03
Preserve the approved standard
Keep the accepted mockup in place or document it thoroughly. Use it to judge deliveries and early production work, not merely as a preconstruction formality.