A scrupper is a built-in opening in a roof edge, parapet wall, balcony, or terrace that allows surface water to drain away from a building. Typically constructed of metal, PVC, or cast iron, scuppers serve as direct outlets for rainwater, preventing ponding and reducing the risk of leaks or structural damage. Unlike traditional gutters, scuppers are integrated flush with the wall or roof edge and can handle large volumes of water during heavy rainfall.
In practice, scuppers are installed at low points along parapets or curbs, where they channel water through the wall and into a downspout, splash block, or scupper box. In residential flat-roof or deck applications, they keep water flowing off terraces and prevent pooling that can deteriorate membrane roofing. In commercial and industrial settings, box scuppers with built-in strainers protect drainage lines from debris and connect directly to leader pipes. Proper installation requires secure flashing and sealant to stop water from seeping behind the parapet, distinguishing a scupper from a simple roof drain that penetrates the deck surface.
During an inspection, I might say: I recommend that each scupper on the south-facing roof be replaced and that the metal flashing be tightly sealed against the parapet to prevent water infiltration.