01
Include the layers below
Ask for a section that identifies the deck or other specified support, relevant framing, and the fastening arrangement. A change in substrate can affect how the selected system is installed. Do not assume that a detail copied from another building remains valid simply because the exposed slate looks similar.
02
Resolve field differences
If opening reveals a different substrate, photograph it and ask the responsible professional to review the detail before work proceeds in that area. Keep the resulting decision with the project drawings. The purpose is not to add paperwork for every piece of slate; it is to make sure the repeated assembly is based on the building that actually exists.