Approach and implementation

Following a detailed site inspection and a root-cause assessment of the issues, we developed a bespoke solution to address the ingress issues.

Chambers either received a polyurethane injection resin to prevent ingress, or an additional application of a polyurea coating, to the internal walls of the chamber after resin injection.

The high-performance polyurethane injection resin reacts with the infiltrating water, forming a hydrophobic, semi-flexible foam that expands, effectively sealing cracks, voids, and joints, where groundwater is entering. With rapid curing properties, the fast-setting resin is ideal for immediate control of water ingress, providing a durable and lasting solution. This ensured that water could no longer penetrate the chamber walls.

After the ingress was controlled, a robust polyurea protective coating was applied to the internal surfaces of some chambers. This coating provides an additional layer of protection, preventing future deterioration caused by moisture exposure, chemical attack, and mechanical wear. The tough, elastic nature of polyurea makes it highly resistant to mechanical wear and allows it to bridge minor cracks that may develop over time, maintaining the integrity of the protective layer it is forming.