Polyurethane Grouting

Polyurethane grouting is the process of injecting expanding polyurethane grout into voided areas or directly under roadways, inside structures or under slabs-on-grade in order to fill voids or relevel slabs. Polyurethane grout is often used in concert with compaction grouting whereby compaction grouting is used to densify the soil at depth where consolidation may be occurring leading to surface settlement, and polyurethane grouting is then used to relevel slabs on grade and fill any existing voids, or voids created by the releveling work. The combination of these techniques thus treats both the cause (by the densification of loose soils) and the symptom (by the filling of voids and releveling) of the settlement. The use of polyurethane grouting only to fill voids and relevel structures near the surface would allow settlement to continue and require additional re-leveling at a later date as the loose soil at depth continued to consolidate.