A roof drainage opening or outlet that allows water to flow from the roof surface to downspouts or away from the building structure.

A scupper is a roof drainage opening or outlet that allows water to flow from the roof surface to downspouts or away from the building structure, serving as a critical component of roof drainage systems that prevent water accumulation and potential structural damage. This essential building element is typically installed through parapet walls, roof edges, or other barriers to provide controlled water discharge from flat or low-slope roofs where gravity drainage is necessary for proper water management. Scuppers are fundamental components in commercial and industrial roofing systems where they work in conjunction with roof drains, gutters, and downspouts to create comprehensive drainage solutions, making them critical elements for building protection, structural integrity, and compliance with building codes that require adequate roof drainage capacity.

Scuppers are utilized in various roofing and drainage applications including commercial flat roofs where they provide primary or secondary drainage for large roof areas, industrial buildings where scuppers handle drainage from manufacturing and warehouse facilities, institutional buildings such as schools and hospitals where reliable drainage is essential for building protection, residential applications including townhouses and condominiums with flat or low-slope roofs, retrofit projects where scuppers are added to improve existing drainage systems, and specialty applications such as plaza decks, green roofs, and architectural features where controlled water discharge is required. Each application requires appropriate scupper sizing, placement, and integration with the overall drainage system.

The design and components of scuppers include the scupper opening that is sized based on drainage calculations and building code requirements, typically rectangular or square in shape, scupper boxes or receptors that collect water and direct it to the discharge point, flashing and waterproofing systems that ensure watertight installation and prevent leaks around the scupper, overflow provisions that handle excess water during heavy rainfall or drain blockages, downspout connections that carry water from the scupper to ground level or storm drainage systems, and protective elements such as screens or guards that prevent debris from blocking the scupper opening. Proper design ensures adequate drainage capacity while maintaining building envelope integrity.

Fun Fact: The term “scupper” comes from the nautical world, where scuppers are openings in a ship’s side that allow water to drain from the deck, and the building construction term adopted this maritime drainage concept for roof applications.