What it involves

The cleaning, structural and hydraulic repair of manholes to facilitate safe traffic and pedestrian loading and to prevent ground/flood water entry and effluent discharge out of sewer systems.

Our Service 

  • Your specification or our survey will determine what is required
  • A full rehabilitation could include:
    • Cleaning and removal of hard deposits
    • Sealing of heavy infiltrations
    • Structural repair of major damage to
    • Sealing of minor infiltrations and
  • Our preferred system is Hermes’ M-Coating
  • Manhole Rehabilitation system
  • Suitable to resolve ground water infiltration, damage caused by neglect and damage from chemical attack by trade effluents and hydrogen sulphide gas (H2S) and debris benching and chamber application of corrosion resistant coating

Our Process

  • The manhole which needs renovating is first flushed, so that it is free of loose deposits. Hard deposits such as concrete and roots are milled away with our robotic cutters
  • The manhole is then cleaned using a rotary spray-head with a nominal pressure of 100 bar (400 litres of water per minute) and a maximum pressure of 700 bar
  • Flow is stopped before or after cleaning depending on the volumes of water produced and normal flow rates
  • The ERGELIT mortar is mixed with water on site. It is pumped by hose from the mixer to the point of application
  • With flow stopped, the spray-lining unit is lowered into position in the manhole where it sprays out the specially-developed ERGELIT material. The quantity of material is adjusted in accordance with the nature of the respective damage
  • The unit is progressively lifted to provide an even coating. Flow can be restored after 4 hours


  • Round and rectangular manhole shafts and chambers from 500mm to 1500mm diameter
  • Up to 10m deep
  • Flow stopped or diverted for circa 4 hours

When to use Manhole rehabilitation

  • When there is supporting evidence or a significant risk of exfiltration through defective manholes causing ground water pollution, or conversely where ground water infiltration washes soil into the sewer system causing voids to be formed around the chambers. The other major risk associated with the structural degradation of manholes is the risk of collapse under loading
  • The major benefits of the M-Coating System from Hermes is the speed of the repairs which causes minimal disruption and gives the manhole a 75-year life span

Why choose the McAllister Group for Manhole repair

People –We have two dedicated manhole rehabilitation teams and a wider pool of manufacturer-trained and experienced staff

Experience – As an early adopter of this system in the UK, the McAllister Group offers customers a robust installation and quality management system to ensure a high quality, right first time installation – over 150 installations per annum bear testament to the assertion

Partners – Hermes provide all the relevant technical support and training, including installation support for unusual situations such as irregular chamber shapes and major voids