Leak Causes
Roof Flashing & Termination Bar Repair
Flashing failures account for the large majority of flat roof leaks — more than any single membrane defect.
Flashing is the material (usually metal or reinforced membrane) that seals the transition between the flat field of the roof and any vertical surface or protrusion — a wall, a vent, a skylight curb. A termination bar is a specific type of flashing hardware: a metal strip screwed through the top of the membrane to hold it firmly against a wall.
The problem is that termination bars and flashing are exactly where different materials and different contractors’ work meet — which makes them the most likely place for something to have been done incorrectly at some point in the roof’s history. Mixing incompatible materials at a flashing transition (for example, patching one membrane type over another without proper preparation) is a common, serious mistake that looks fine initially but fails within a season or two.
A proper flashing repair means removing the failed section entirely, addressing whatever’s underneath (cleaning off old tar, mastic, or degraded material), and rebuilding the transition with compatible materials applied correctly — not layering a new fix on top of an old failure.
Why Mixed Materials at a Flashing Transition Are So Common
Flashing repairs done over the years by different contractors, or as DIY attempts, often introduce incompatible materials at the same transition point — a later EPDM patch over an original torch-down membrane, for example, without the proper primer or transition strip to bond them correctly. Each layer might look fine on its own, but the interface between mismatched materials is exactly where separation happens.
When we find this kind of layered, mixed-material history at a flashing point, the repair usually means removing back to a clean, single, compatible surface rather than adding yet another layer on top of an already-compromised transition.
Common Questions
How can I tell if my roof has mixed materials at a flashing point without professional inspection?
It’s genuinely hard to identify confidently without experience working with these systems — different membrane types can look similar to an untrained eye, especially under a layer of coating or sealant.
Is it more expensive to repair a flashing point with a history of mixed materials?
Sometimes, since it may require removing multiple layers to get to a clean starting point rather than a straightforward single-layer repair.
Suspect This Is Your Leak?
We diagnose the exact cause before recommending any repair.