Define the requirement
Start with the exact weathering steel site drainage details requirement, the intended environment and the visible finish. Put dimensions, quantities and the relevant drawing revision in the inquiry.
Coordinate fabrication and installation
Confirm datums, edges, holes, joints, drainage and access before cutting. A short approved sample or marked drawing can prevent avoidable changes during production.
Record the acceptance basis
Separate appearance review from material certificates, dimensional inspection and packing requirements. Keep the agreed specification with the quotation and handover documents.