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Big Daddy RD-800 Single Cut-out Dual Roof Drain

Big Daddy, the single cut-out large capacity RD-800 Series epoxy-coated cast iron dual roof drain/overflow combination, more effectively limits the risk of leakage and roof damage than multiple single roof drain and overflow units. Because its innovative design requires just one cutout, installation is faster, resulting in lower installation costs. The sturdy drain construction reduces the risk of job site issues while ensuring durability. Unlike competitive dual roof drains, the Big Daddy has a low-profile drain body, allowing installations anywhere a standard roof drain can be used. The RD-800-CT provides overflow through the dome.

*Based on independent lab tests conducted November 2018 using 6” standing water and 10” outlet model.


  • Up to 1368-gallon-per-minute (GPM) flow rate*
  • Single cut-out design for less roof cutting
  • Faster installation, resulting in lower installation costs
  • Low-profile drain body allows for more installation applications
Series Specifications
Application Dual Roof Drains

Select a Model

Select options below to identify the UPC, Order Code, and Repair Kit for a specific RD-800

Approval Information

For approval information, please refer to the products specification sheet. For any other information on product certification and documentation information, please visit our certification partner websites: