Polyurethane (PU) Injection Systems basically come under "remedial waterproofing" and are extremely effective in mitigating active water leakages that commonly occur in reinforced concrete elements such as basement retaining walls, podium/raft/roof slabs, construction joints, cold joints, liquid retaining tanks, swimming pools, water treatment plants, pipe inserts and penetrations, etc. In fact, PU injection is sometimes referred to as the "last line of defence" against nagging and recurring active water leakages that have remained unresolved even after the use of cement based grout materials and methods.

The system comprises polyurethane (PU) foaming or non-foaming, single- or two-component, resin combinations. These PU resins are injected through compatible pumps, packers, and other accessories into the sections of the reinforced concrete element that exhibits active water leakages or damp patches from the “negative side” or from the egress side of the leakage.

PU resins undergo chemical reactions in the presence of water/ moisture/ humidity present inside the reinforced concrete element. These foaming PU resins expand and cure by forming dense and closed celled foam. This dense foam occupies and blocks all pores, interstices, and small voids present inside the concrete element and effectively mitigates the water leakage. Non-foaming PU resins can then be injected at the same locations as a secondary injection process to ensure that a sound and integral leak mitigation process has taken place.