Manholes cover the access shafts that allow technicians to clear and maintain our drainage and sewerage infrastructure. Keeping them clear and structurally sound is important for ensuring public safety – falling into one of these shafts can cause serious injury. It is also vital for preventing groundwater or flooding from forcing discharge out of our sewer systems. Manholes with significant structural damage may be prone to collapse under loading.

McAllister manhole rehabilitation service ensures that your drainage access points are kept in good working order. Our full rehabilitation service includes:

  • cleaning and removing hard deposits.

  • sealing against infiltrations.

  • structural repair of major damage

Our preferred system is Hermes M-Coating. This system helps to:

  • resolve groundwater infiltration

  • reverse the damage caused by neglect or the corrosive effects of trade effluents and hydrogen sulphide gas

  • provide a corrosion-resistant coating to the sewer benching

Our technicians can get to work on round or rectangular manholes with shafts and chambers from 500 mm to 1500 mm in diameter, and up to 10 m deep. They will require the flow to be stopped or diverted for about 4 hours.

They begin work by flushing the manhole of loose deposits and using robotic cutters to grind away hard deposits such as concrete and roots. They then clean the manhole with a rotary spray-head with a nominal pressure of 100 bar – around 400 litres of water per minute.

They mix ERGELIT mortar on site, pump it through a hose, and into the inside of the manhole. They regulate the flow to ensure they use just enough mortar to repair the damage. They slowly lift the mortar application unit to ensure an even coating. The mortar takes about 4 hours to set, at which point the flow in the sewer can be restored.

We boast two dedicated manhole rehabilitation teams, and a broader team of technicians who have received training from Hermes – the M-Coatings system’s manufacturer. They provide all technical support and training, including installation support for unusual situations, such as irregular chamber shapes and major voids. We were an early adopter of this system in the UK and we offer a quality installation and management system, as over 150 such installations each year can attest.

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