What it involves

Restoring deformed pipes, usually made from pitched fibre and laid between the 1950s and 1970s, to their full diameter without excavation and installing a new rigid pipe within the re-rounded original to give it a new 50 years plus life.

Our Service 

  • A head, or ‘pig’, of the same diameter as the original pipe, is winched through the offending section
  • When the original shape has been restored after one or more passes, any debris arising from areas that were previously blistered or delaminated is removed
  • A CIPP or slip liner is then installed to create a new structurally sound pipe

Our Process

  • A Survey of the host pipe is carried out to assess the condition, original shape and connections to the run to be re-rounded
  • Initial cleaning should be carried out to remove any silt from the run
  • A line should be sent through the run from the winching end to the upstream manhole
  • The pig should be attached
  • The pig should be winched through the run, not
  • exceeding the predetermined maximum pressure
  • If necessary, pigs of progressively increasing diameters can be used.
  • Once the pipe has been temporarily restored to its original state (pig will run through easily), debris should be cleared
  • A CIPP or slip liner should then be installed
  • Any connections covered should be reinstated
  • A post works CCTV survey should be carried out


  • Pipes from 100mm to 450mm diameter
  • Flow stopped or diverted

When to use pipe re-rounding

  • When a low strength pipe is partially crushed, blistered or delaminating. Depending on the re-rounding method, care should be taken if there is a risk of voids around the pipe
  • The major benefits are the low disruption for the asset owner/users and relatively low costs in relation to excavation depending on the depth and route of the pipe. The environmental benefits of re-using the existing infrastructure are considerable

Why choose the McAllister Group for Pipe Re-rounding?

People – Our senior staff possess years of experience in successfully re-rounding pipes throughout Southern England. The insight and expertise gained coupled with the breadth of issues encountered has allowed us to develop our own bespoke equipment to counter these problems.

Experience – Re-rounding is an activity where experience is king. We possess this experience in-house across our GB and Ireland teams who have worked with a wide-range of piping

Approach – Our approach and advice remain objective. We seek to overcome any obstacles and deliver the optimised outcome for our clients