All Dam Buster Side Outlet devices are pre-engineered and must be used in combination with a correctly sized Dam Buster rainhead to achieve compliance.  

So long as the overflow device comprising a Dam Buster Side Outlet and a Dam Buster Rainhead is selected in accordance with the design chart for the Dam Buster Rainhead (for the total design flow rate in all the box gutters), the Dam Buster Side Outlet automatically has sufficient hydraulic capacity for any allowable combination of flow rates. 

All box gutters discharging to a Dam Buster Side Outlet sump must also be designed for ‘free flow’ in accordance with Figure I1 of AS/NZS 3500.3-2018.

No Performance Solution Needed

Dam Buster side outlets are Deemed to Satisfy devices which use the power of gravity to change the direction of water flow in box gutters without any Performance Solution.   

Side outlet devices are not only adjustable on site, but available in varying sizes to suit all box gutters 200mm to 600mm wide.  Like all Dam Buster products, they will suit virtually any installation, new or retrofit. 

Available Shapes: 

  • "T" shape (as shown on the left and in the video below), with two box gutters discharging to the device and then to a single outlet point
  • "L" shape (‘left’ or ‘right’ handed*), with one box gutter only discharging to the device i.e. the device is located at the end of a box gutter and used to change direction 90 degrees
  • “Crucifix” (or "+") shape, with three box gutters discharging to the device (for example, where the device is located at the party walls in a row of terrace style houses, having hip ended roofs at the front or rear parapet wall)

* The ‘hand’ is determined by the change in direction of the water flow at the device, as viewed from the upstream end of the box gutter.

Used in series or in combination, virtually any box gutter directional discharge problem can be solved compliantly and easily, even in a retrofit situation.  


Dam Buster is currently developing an amazing, easy to use calculator for the design of box gutters discharging to a Dam Buster overflow device, and this will be available in the near future!  Ensure you watch our web site and Facebook page for more details. 

"T" SIDE OUTLET (retrofit)

"T" SIDE OUTLET (retrofit)
L shaped "R" side outlet (retrofit)

L shaped "R" side outlet (retrofit)

Watch How It Works!


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