Commercial Roof Leak Repair

Finding the source of a commercial roof leak is harder than it looks. Water enters the membrane at one point and travels through the insulation stack to appear on the ceiling somewhere else. We trace it to the source.

The most common complaint we hear from Atlanta building managers is that their previous roofer repaired a leak and it came back within two months. The repair did not fail - the wrong location was repaired. On a commercial flat roof with 2 to 4 inches of polyiso insulation above the deck, water that enters through a failed flashing or a seam breach does not fall vertically to the ceiling below the entry point. It travels horizontally through the insulation, under the membrane, and finds a low point - a deck seam, a pipe penetration from below, a light fixture opening - before it appears as a water stain on an interior ceiling tile. The stain is rarely below the entry point.

Leak tracing on commercial roofs is a diagnostic process before it is a repair process. We look at the interior stain location, map it to the roof area above, then work backward from that area looking for the failure mode most consistent with the leak pattern: perimeter flashing at the nearest parapet wall, the closest pipe penetration, the nearest HVAC curb flashing, a seam junction. Atlanta's summer thunderstorm pattern - concentrated, high-intensity events - helps with diagnosis because owners can usually tell us whether the leak correlates with specific wind direction, whether it only happens on heavy rain, and whether it appeared immediately after a recent rooftop mechanical trade visit. That information usually narrows the field significantly.

We respond to emergency leak calls across the Atlanta metro from our 191 Peachtree St NE office. Downtown, Midtown, and Buckhead calls get crews on-site within four business hours during normal business hours. Buildings within the I-285 ring - Sandy Springs, Dunwoody, Decatur, East Atlanta, College Park - see same-day mobilization. Outer metro locations are next-day at the latest. Emergency after-hours response is available for occupied buildings where active water intrusion is affecting operations.

Interior mapping first: We start inside the building, documenting the location and pattern of interior water staining. On a building with a grid ceiling, we can map the stain to within 2 to 4 feet of the actual ceiling tile coordinates. On an open-ceiling or industrial building, we look for wet insulation, stained deck, or rust streaks on structural members. We photograph the interior evidence and record it before going to the roof.

Roof zone identification: We translate the interior stain location to roof coordinates using the building's column grid or structural bay pattern. The entry point on the roof is almost never directly above the interior stain - on buildings with slope-to-drain, water migrates toward the low point, which may be 20 to 40 feet from the entry point on a tapered insulation system. We identify the probable entry zone - the upslope area above the interior stain location - and work from there.

Failure mode investigation: In the identified zone, we look for the failure modes most likely to produce a leak at that location: lap seam stress at the membrane edge, flashing separation at a parapet base, failed boot flashing at a pipe penetration, deteriorated sealant at a counter-flashing termination, inadequate back-nailing at a coping cap. We probe membrane edges, flex flashings, and squeeze-test seam sections to find material defects that may not be visible without physical contact.