01
Record the profile before work
Photograph ridges, hips, dormers, gables, and visible eave lines from useful viewpoints. Note any changes in slope or roof form. These features can influence how the building reads even when individual slate pieces are difficult to see.
02
Connect the profile to the proposed scope
Ask the designer whether changes to substrate, build-up, or details would alter the visible outline. Review significant changes with the appropriate preservation professionals. Keep the existing photographs alongside the proposed sections. Preserving character may require attention to the profile and junctions as well as matching the field slate, especially on roofs that dominate the building's appearance.