01
Approve a range of material
Review several representative pieces and ask about differences in color, surface texture, thickness, and weathering. Discuss how the lot will be sorted and blended. A single unusually smooth or uniform sample may not represent the delivered selection. If a more consistent appearance is essential, make that priority explicit before the supplier confirms the order.
02
Define what needs further review
Agree how unusual pieces or deliveries outside the approved selection will be handled. Keep the accepted samples and photographs on site. Judge the roof at relevant viewing distances as well as close up, while leaving condition and technical acceptance to qualified professionals. Clear expectations make it easier to distinguish intended natural character from a genuine mismatch or an unsuitable piece.