Why Overflow Drains Are Used on Low-Slope Roofs
Overflow drains are part of a building’s roof drainage system and are commonly installed alongside internal drains on low-slope commercial roofs, either as scuppers or secondary internal drains.
Property owners often hear the term during roof inspections, drainage evaluations, or when reviewing building codes for commercial roofs. Many building codes require overflow drains to protect the roof from excessive water weight if the primary drains fail.
Without overflow drainage, blocked primary drains allow water to pond on the roof. This can result in water infiltration or even roof collapse in extreme cases, which is why overflow drains are considered a critical safety feature in modern roof design.