Departure from traditional drainage

Into every life a little rain will fall. By designing the EDGE commercial aluminium window and door systems with this fact of life in mind, we incorporated a more practical and reliable solution to deal with water, be it from rain, humidity or condensation.

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Another EDGE innovation is our frames rainwater evacuation system, Watershed. Watershed is designed to manage and re-direct the flow of rainwater through the frame system to the external perimeter of the building. The concealed transom drainage system re-directs water over and around the edge of glass.


  • The Watershed component is designed to be factory fitted during transom assembly, increasing quality control and decreasing costs.
  • Once properly assembled, Watershed ensures water cannot run from the end of the transom on top of the glass or the glazing wedge.
  • Watershed eliminates ugly external drain holes in the face of sills and transoms. Treating windows as “fish tanks” with silicon glazing doesn’t stop water entry and external drain holes actually become an entry point for water. Good system design allows water entry and effectively deals with drainage.
  • Watershed allows the safe passage of water in front of the glass, using vertical members (jamb and mullion) to direct water through the system for collection by the subsill.
  • Watershed can be fitted after frame assembly, a huge benefit if it is inadvertently forgotten during assembly. It can be snap fitted into the pocket above the transom and slid into place. This is not the preferred and recommended process, though and requires more careful caulking.


Where air goes, water will follow

The Watershed methodology ensures dry interiors and prevents the build up of still water, recurring condensation and even mould that can occur in standard framing systems.

Discover more about EDGE Architectural’s product range here.