What is the purpose of a roof drain?

The purpose of a roof drain is primarily to discharge water into a leader or conductor. Roof drains are critical components of a building's drainage system, specifically designed to remove excess rainwater from roof surfaces. By directing the collected water into a vertical downspout (the leader or conductor), the system effectively manages the flow of water, preventing ponding on the roof.

This function is essential for maintaining the structural integrity of the building, as stagnant water can lead to leaks, mold growth, and damage to roofing materials. By transferring excess water away from the roof, the drain also supports the overall drainage system of the building, ensuring that rainwater is efficiently routed to appropriate drainage areas, such as storm sewers or retention systems.

While preventing flooding and collecting rainwater may seem plausible, they are not the primary role of the roof drain. The focus is on the safe and effective discharge of water, which helps mitigate the risks associated with excessive water accumulation on the roof, thereby protecting the building.