Injection Chamber Waterproofing

Introduction

A drinking water injection chamber operated by Wessex Water was experiencing persistent groundwater ingress at wall-floor joints and surrounding concrete substrate. Left unaddressed, ingress of this nature compromises structural integrity and contaminates potable water infrastructure. UCL Ltd were engaged to stop active water infiltration and apply a DWI-approved protective lining system.

Our Solution

Active groundwater ingress was first arrested by injecting closed-cell polyurethane resin into concrete voids using an electric pump. On contact with groundwater, the resin expands to fill voids completely, halting further infiltration. The chamber interior was then high-pressure water jetted at a minimum of 7,000 psi to produce a clean, profiled substrate capable of achieving adequate coating bond strength. Residual water, grit and debris were removed by pump and wet/dry vacuum. Flexcrete 851 cementitious coating — Drinking Water Inspectorate (DWI) approved — was hand-applied at a consistent 2mm thickness across all floor surfaces, walls, joints and pipework penetrations.

Key Benefits

• Groundwater ingress fully arrested prior to coating application, eliminating risk of coating failure
• 7,000 psi high-pressure jetting ensured substrate compliance and strong coating adhesion
• Flexcrete 851 applied at controlled 2mm thickness across all critical interfaces
• DWI-approved coating system maintains potable water safety compliance
• Rapid project turnaround met Wessex Water's operational requirements
• UCL Ltd retained as preferred contractor for additional chamber lining works across further Wessex Water sites

Conclusion

The injection chamber was returned to full service with groundwater ingress eliminated and a compliant DWI-approved lining installed. UCL Ltd's capability in combined resin injection and protective coating works has secured ongoing framework activity with Wessex Water.