Coombe Boys School, New Malden

• Pile caps and ground beams
• Below ground drainage including 643m3 attenuation, headwall into stream, hydrobrakes, and extensive realignment of drainage
• Install of PC perimeter ground beams and PC lift pit to modular design
• Ground floor slab
• HD bolts for steel frame
• Set-up for temporary accommodation units to allow old buildings to be demolished
• External works and Muga pitch prepartion

A pipe jacking solution was adopted to allow a 3m-deep foul run to be installed beneath a public road without disrupting access.

• Trenchless installation of underground pipework using hydraulic jacks to push prefabricated sections into place

• 125mm PE100 pipe sections welded into a continuous run, with weld tests performed for quality assurance

• Excavation within a shielded tunnel boring machine, progressing between a launch shaft and a reception shaft

• Connection formed from the reception shaft to the public sewer

This trenchless method minimised surface disruption, reduced environmental impact, and maintained access to the school throughout. JPD have successfully used this technique across multiple projects where pipelines must cross beneath roads, railways, or rivers.

From the final foul manhole, a connection was made to the existing sewer within the public highway:

• All applications, licences, and fees handled by JPD

• Drain run installed below live services without disturbing the road surface

• Specialist mining operation using a rail and trolley system supported by robust temporary works designs

• Final connection achieved via saddle connection, before careful reinstatement

Due to the density of live services around the existing substation, vacuum excavation was adopted to minimise risk. This technique uses pressurised air or water to loosen soil, which is then removed with a vacuum hose.

• A safer, non-destructive alternative to mechanical excavation

• Protects sensitive utilities such as gas, water, and electrical supplies

• Environmentally friendly and precise, widely used by JPD on infrastructure and education projects

Given the site’s operational school setting, works were carefully planned and executed to ensure safety and minimise disruption:

• Construction areas securely segregated from school grounds with hoarding and exclusion zones

• Deliveries restricted outside of busy school drop-off and pick-up times

• Noise and dust minimised through adapted working methods

• High behavioural and safety standards maintained by all operatives

JPD bring extensive experience of working in live education settings, having successfully delivered projects at Green School for Boys, Waldegrave School, Twickenham College, Kingston University, and Sutton Secondary School.