01
Compare the important attributes
Ask for the substitute's actual dimensions, thickness selection, source information, relevant product documentation, and representative samples. Have the installer explain any effect on layout, fastening, quantity, or flashing relationships. If the original material was selected for a historic match, include the preservation decision maker in the review before ordering.
02
Update the project record
Document what was approved and replace outdated descriptions in the working scope. Keep samples of both selections where they help explain the decision. Confirm whether other components or delivery dates change as a result. A substitution that works well can still create confusion if invoices, drawings, and spare-stock labels continue to describe the original product.