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How to create the downpipe offset from a roofline in steel

Swan neck Bend Offset

The roofline of a building, where the gutter is fitted, is commonly positioned away from the wall of the house beneath it where the downpipe needs to be attached.

The distance away from the wall varies depending on the architects design of the house.

Offsets in the steel range come in 4 options:

  1. 60mm = a ‘fixed’ offset – in 80mm and 100mm dia pipe
  2. 60-210 (or 255*) mm = For slightly larger projections a ‘swan neck’ offset can be created using 2 pipe bends and varying the angle/’twist’ of the swan-neck away from perpendicular (90°) to the wall
  3. 500-700mm = NEW 2 part, Variable offset
  4. >700mm = For larger projections still, an offset can be created using a cut length of pipe inserted in between the 2 pipe bends

2. Max offfsets using two x 70 degree bends (i.e.GST80B70) make a ‘swan neck’ to offset the downpipe from the roofline to the wall of the building.

  •  In the 80mm diameter downpipe 2 bends make a maximum of 210mm offset
  •  In the 100mm diameter downpipe 2 bends make a maximum of 255mm* offset

N.B. The height of 2no. 70 degree bends together to create a swan-neck offset is 240mm

For any other offset between 60mm and the maximums mentioned above you should pivot the ‘swan neck’ inside the downpipe to whatever distance from the wall is required to meet the outlet at the roofline. So that the running outlet or prefabricated outlet is not directly above the downpipe but set off to the side as necessary.

Steel Offset Bends measures table

3. The NEW 2-part, Adjustable Offset – Rainclear have worked with the manufacturers to create a 2-part, adjustable Offset – in Galvanised Steel, the 7 Robust Coated Galvanised steel colours, and the 80mm and 100mm diameter pipes – to add a solution for offsets of up to 700m.

4. For even larger offsets, as in the case study in Aberystwyth, a cut section of downpipe can be inserted between the two bends, cut to whatever additional length is required

(N.B. remember to allow for the overlap of the swaged necks of the downpipe piece and of the bends in your calculations).

Read more about how to measure the projection/offset you’ll need: https://www.rainclearsystems.co.uk/how-to-measure-the-offset/

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