Which perimeter component is failing?
Coping caps, gravel stops, fascia, edge flashing and gutters perform related but distinct functions. Identify which component is present and where the reported water enters. A loose joint at a coping corner is not the same repair as a separated membrane termination, a bent fascia panel or a gutter outlet that no longer carries water. Photographs should capture the entire transition and a close view of the affected joint or fastener.
Check for open seams, corrosion, loose or missing attachment, displaced sections, failed sealant and deterioration in the nailer or substrate. Also look for signs that material movement or prior work changed the metal geometry. Check the backing and substrate beneath the visible cap as well as the metal itself. If the backing is wet or unstable, it may need repair before replacement metal can be secured and the roofing membrane terminated.
Map each perimeter by elevation or roof section, recording examined runs, included work and areas access prevented us from reviewing. This prevents a detail repair from being mistaken for complete replacement of all perimeter metal.