A good repair can add years to a flat roof. But at some point, every dollar spent on patches is a dollar that would have been better spent on a new roof. Here are the signs we look for during an inspection.
First, wet insulation. Once water gets under the membrane, the insulation soaks it up, loses its value, and starts to rot the deck. If a large share of the roof is wet, repairs only seal the water in.
Second, leaks in more than one place, year after year. One leak is a repair. Leaks that move around the building mean the membrane or the seams are failing across the whole roof.
Third, ponding water that sits for days after rain. Standing water speeds up aging and points to drainage or deck problems that a patch can't fix.
Fourth, a membrane that's cracked, shrunk, or pulling away from the edges and curbs. Fifth, age: a roof near the end of its expected life will usually cost more to keep patching than to replace on your schedule instead of in an emergency. A thorough inspection with photos is the best way to decide.