Proper roof maintenance encompasses regular inspections of masonry flashings and membrane terminations. The large parapet wall is on a roof in Harlem. Moisture readings along the base of the wall indicated a high percentage of moisture. The readings were confirmed with a test cut which revealed saturated perlite insulation. The build of the roof is gravel-surfaced BUR, two layers of 1.5" perlite over a mopped vapor barrier on a concrete deck. Such construction can mask the degree of water infiltration as it slows or stops the water's passage into the building. A new stainless steel wall flashing had been installed but it may have been done after the damage was caused or not be properly installed.
In scenarios like this roof in Harlem it is worth investing not only in annual roof inspections, but also annual moisture surveys. This way problems can be detected and remedied early and costly repairs and further damage can be avoided.