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Waterproofing and Repairing Leaks with Grouts

The use of polyurethane grouts can stabilize soils, fill voids, and seal leaking infrastructure. A common but poorly understood method of repair uses polyurethane chemical grouts that react with water. They either bond with the concrete to create a permanent seal or become rigid to fill voids, stabilize soil and protect against water damage. Since 1955, it has been used in sewers, manholes, tanks, and tunnels around the world. Over 40 years after its development, the procedure remains an effective, long-term solution for preventing groundwater from infiltrating into sewer systems.

Methods of reducing infiltration

Municipalities are increasingly seeking ways to limit groundwater infiltration into their water supply systems. Infiltration is the entry of groundwater into a sewer system through leaks in lines, manholes, pump stations, and storm drains. In addition to adding to treatment costs and increasing the risk of sanitary sewer overflows, infiltration further compromises the integrity of a pipe’s structural strength. The presence of groundwater can also cause leaks, which carry sand, silt, and other debris into the system, increasing wear and tear on equipment. Pipes that leak cause voids and, in severe cases, can undermine a structure, leading to unstable foundations and settlement.

Research shows that manholes are a major source of groundwater infiltration in sewer systems. Waterproof liners are often used in repairing leaking basements, but groundwater infiltration must be eliminated prior to installing the lining. Contractors often use a quick-set hydraulic cement to temporarily stop leaks, giving them enough time to install a new lining. Although the patch may seem like an effective way to repair a damaged lining, it is actually quite temporary and can result in a weak bond between the patch and the wall. Polyurethane grout can be used to seal leaks in a matter of seconds, permanently and with immediate cost-savings.

Usage of Polyurethane Grout

Polyurethane chemical grouts are sold in liquid form and injected into or around leaks. A chemical reaction occurs when the resin comes into contact with water, producing a closed-cell foam. The foam can be flexible, resilient, or rigid, depending on the type of surfactant used.

To fix a leak, an injection hole is drilled near the source of the leak, and the chemical grout is injected through the wall into the water source. The force of the water is channeled into the structure, which pushes material back into the wall, sealing it against leaks.

Grouting will continue to be one of the easiest, most cost-effective and longest-lasting repair solutions available to Singapore’s infrastructure as it ages. Contact Le Fong Building Services for your grouting solution to your leakage today!