Describe the leak and most causes can be narrowed before anyone climbs anything.
A stain on a ceiling. Someone had already been out, sealed the spot directly above it, and left. It stayed dry for a season. Then the rain came in from a particular direction and the stain came back a little wider than before.
It came back because the sealant was never near the leak. Water gets in at a flashing or a lap, runs along the decking, and drops wherever the structure lets it — often several feet from where it entered. Patch the stain and you have sealed the exit, not the entrance.
So we built the business around the part everyone skips: finding where the water actually gets in, confirming it before opening anything up, and repairing that. It takes longer at the start and it is cheaper by the end. In a city built as tightly as Passaic — shared roof lines, rear additions, parapets on every downtown block — it is the only approach that holds.
That is the whole business. Roof leaks, traced properly, in Passaic and the towns around it.
Before anyone climbs anything, these do more to identify a roof leak than a photograph of the ceiling: where the stain is, which floor it is on, when it first appeared, and what the weather was doing at the time.
The last one is the one people leave out and the one that helps most. A leak that only shows in driven rain from one direction is a flashing lap or an upstand. One that tracks heavy rainfall whatever the direction is usually drainage. One that appears on cold, still, dry nights is very often condensation rather than a leak at all.