The high quality Cast Iron Roof Outlet range, featuring medium sump and large sump bodies, two-way outlets, balcony outlets and an extensive range of loadbearing grates

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Key Points


  • The medium sump range is a compact outlet body in vertical and horizontal variations
  • The large sump range provides a deeper sump for 100 and 150mm vertical pipe
  • Two way outlet is suitable for use in a parapet wall construction
  • Provide flat roof drainage for warm, cold and inverted roofs
  • For flat roof structures with insitu cast concrete, timber or lightweight metal deck construction
  • Ideal for use with copper and lead clad roofs where the risk of bi-metallic corrosion is high
  • Load bearing applications where rainwater outlets are exposed to vehicular traffic
  • Ideal for connection to continuous waterproofing systems (Single layer, built up felt, mastic asphalt or single ply)
  • Compatible with Harmer SML lightweight cast lightweight cast iron drainage systems
  • The Harmer cast iron range is cast to BS EN 1561 and are suitable for most types of flat roof drainage
  • Designated load rating up to 12.5 tonnes
  • Medium and large sump outlet bodies are available with varying flow rate capacity
  • Cast iron has a proven track record for its longevity over the lifetime of the building
  • Cast Iron is 100% recyclable
  • The crystallised nature of cast iron gives the material very high strength and robustness
  • Once installed cast iron components resist impact damage even in exposed areas
  • All Harmer cast iron clamps and grates are surface treated using a sherardizing zinc coating which provides an extremely hard wearing anti corrosive finish
  • Domical grates are made from UK-stable polypropylene to give long life service
  • Two way outlet rectangular grate available in sherardized cast iron, nickel bronze or mill finish aluminium. Aluminium grates can be polyester powder coated upon request
  • The outlet flanges only have a primer coating, so the contractor / installer should protect or coat it during installation
Installation & Fixing


  • Easy and quick to install
  • Low maintenance