A common method for applying grout is to drill a hole next to the leak, inject the material through the hole with water pressure, and then use a trowel, sponge, or other tools to work it into the crack. The oldest method of repairing concrete structures often requires the use of polyurethane chemical grouts. These grouts react to water and eventually harden into a solid like substance. They bond with concrete to form permanent seals that are either flexible or rigid, depending on their intended use.

Since 1955, it has been used as a sealant in sewers, manholes, tanks, vaults, tunnels, and many other applications. More than 40 years of experience show that polyethylene still provides the most cost-effective, long-term defense against water infiltration into sewer systems.

Many contractors often use quick-set hydraulic cement to stop the leak temporarily and buy them enough time to install the new lining. The short-term use of a patch such as this can result in a weak bond and failure of the lining system. Polyurethane grout is effective at stopping leaks permanently and with immediate cost-savings.

Usage of Polyurethane grout

Polyurethane chemical grouts are usually injected into the source of the leak or into areas surrounding the leak. When resin contacts water, it forms a chemical reaction that causes the material to expand into an open-celled foam. Foam can be made hydrophilic, or water-loving, by adding surfactants; it can also be made hydrophobic, or water-repelling, by adding more surfactants. In most cases, water flowing through a leak in a manhole can be used to pull grout into the structure. To stop a leak, a hole is drilled into the water source close to where the leak is occurring. Chemical grout is then injected through the wall into the water source with a syringe.