What condition must the existing roof be in?
Start with a close review of the surface and the layers that can be inspected. Identify the roof system, prior coatings or overlays, seam condition, penetrations, edge transitions and areas where water remains. Look for delamination, open laps, loose attachment, corrosion, surface contamination or material that no longer provides a sound base. These observations determine whether local repair, broader removal or a coating evaluation is the next useful step.
A coating does not repair every underlying assembly problem. Wet insulation, deteriorated deck, unstable membrane or a failed flashing detail may need correction before restoration, and some conditions may make coating inappropriate. If a small test area or adhesion check is part of the selected system's process, identify who approves the location and how results will be interpreted. Do not treat a color change or continuous appearance as proof that concealed conditions have been corrected.
If roof zones differ, document their assemblies separately rather than assuming one coating specification applies everywhere.