Hercules®-Plus Roof Drain

The industry’s most popular RetroDrain now provides greater water flow.

With integrated vortex breaker technology, the Hercules-Plus RetroDrain can provide up to 2.5 times greater water flow to reduce excessive water and weight from the roof faster. In addition, the vortex breaker can reduce “chugging” which can damage the plumbing system. The drain features a one-piece spun aluminum body, “safety yellow” cast aluminum strainer dome, and heavy duty clamping ring for strength and durability. Hercules-Plus RetroDrains incorporate U-Flow® Seal technology for a mechanical watertight connection to PVC or cast iron pipes to prevent water from backup damage. Available in 3-, 4-, 5- and 6-inch sizes.

Hercules-Plus RetroDrains are also available with a TPO or PVC coated flange for direct membrane attachment.

Features & Benefits

  • Water flow is up to 2.5 times faster versus the original Hercules Drains.
  • One-piece seamless body provides strength and durability without separation of the flange from the stem. 
  • Extra-large 17.5-inch flange allows positive attachment of roof flashing membrane while the sump area facilitates drainage. Also available with TPO and PVC coating for direct membrane attachment.
  • Bright yellow strainer domes are cast aluminum for strength and durability, and remain visible on the roof for improved safety.
  • 12-in. long drain stem accommodates most existing field conditions with longer lengths available.
  • Incorporates U-Flow Seal technology for a secure, watertight connection.
  • Saves time and money by allowing easy installation from the rooftop without disturbing occupants.

Interactive Comparison Chart

Drain Size Selector Tool

Physical Data
Ordering Info
Downloads & Videos


Hercules-Plus RetroDrains are designed to replace existing new construction drains in re-roofing applications. Installed from the roof surface, Hercules-Plus RetroDrains are engineered to be installed without removing the existing drain fixture. Hercules-Plus drains have a mechanical seal for direct connection to existing PVC or cast iron plumbing that meets the ANSI/SPRI RD-1 standard.

As with all building materials, it is the responsibility of the installer to review product use with a design professional to confirm safety, compatibility and acceptance with the roof cover manufacturer and local building codes.

Physical Data

Head of Water (in.)3-in. Hercules4-in. Hercules5-in. Hercules6-in. Hercules
1 30 43 35 28
2 74 76 94 110
3 110 188 149 243
4 138 299 295 597


Head of Water (in.)1 Sq. Feet5 Sq. Feet10 Sq. Feet20 Sq. Feet
1 5 130 520 2081
2 10 260 1040 4162
3 16 390 1561 6243
4 21 520 2081 8324


  • Flow performance improvement is not linear across all drain sizes due to the one size fits all design of the strainer.
  • Flow performance is influenced by various factors such as the transition radius and seal sizing variations.
  • Drains with smaller stem diameters develop a choke point sooner than the drains with larger stem diameters thereby making the Vortex Breaker Strainer more effective on smaller drains.
  • Tested by PRI Construction MaterialsTechnologies LLC (Tampa, FL) in accordance to ASPE/IAPMO/ANSI Z1034-2015 Test Method for Evaluating Roof Drain Performance and conducted in accordance with Section 4.1 "Vertical-Pipe Roof-Drain Test."

Ordering Information

SKUDescriptionSize (in.)PackagingDimensional Weight (lbs.)
HDAL3V Aluminum Herc. w/ Clamping Ring 3 Each 27
HDAL4V Aluminum Herc. w/ Clamping Ring 4 Each 27
HDAL5V Aluminum Herc. w/ Clamping Ring 5 Each 27
HDAL6V Aluminum Herc. w/ Clamping Ring 6 Each 27


SKUDescriptionSize (in.)PackagingDimensional Weight (lbs.)
HDTPO3V Herc. w/ TPO Coated Flange 3 Each 27
HDTPO4V Herc. w/ TPO Coated Flange 4 Each 27
HDTPO5V Herc. w/ TPO Coated Flange 5 Each 27
HDTPO6V Herc. w/ TPO Coated Flange 6 Each 27


SKUDescriptionSize (in.)PackagingDimensional Weight (lbs.)
HDPVC3V Herc. w/ PVC Coated Flange 3 Each 27
HDPVC4V Herc. w/ PVC Coated Flange 4 Each 27
HDPVC5V Herc. w/ PVC Coated Flange 5 Each 27
HDPVC6V Herc. w/ PVC Coated Flange 6 Each 27


SKUDescriptionSize (in.)PackagingDimensional Weight (lbs.)
HDCU3V Copper Herc. w/ Clamping Ring 3 Each 27
HDCU4V Copper Herc. w/ Clamping Ring 4 Each 27
HDCU5V Copper Herc. w/ Clamping Ring 5 Each 27
HDCU6V Copper Herc. w/ Clamping Ring 6 Each 27


Physical Data:

The data below is constant for each Hercules RetroDrain

Drain Body 11 gauge (.125-in.) spun aluminum, .032-in. spun-punched copper (3- & 4-in.), or .050-in. spun-punched copper (5- & 6-in.)
Seal Watertight U-Flow mechanical seal (requires U-Flow screwdriver for installation)
Flange 17.5-inch diameter with sump area. TPO and PVC coated options available.
Strainer Dome Yellow Vortex Breaker made of cast aluminum
Stem 12-in. length
Clamp Ring Cast aluminum where applicable. *Not provided on TPO or PVC coated drains.

Go back

Product 2 of 19

Superior productivity. Superior performance.