Hollow-sounding slabs, dropping edges and gaps under concrete usually mean the ground beneath has washed away. Our void filling service injects polyurethane resin into the gaps left by erosion under concrete and water washout, then stabilises the soil so the slab is fully supported again.

We drill small holes through the slab and inject a high-density polyurethane mixture. It flows into the voids, expands to fill them and hardens quickly, restoring support under the slab. As it expands, it also compacts loose and weak soil around it, firming up the ground the slab sits on and reducing future settlement and movement.

Polyurethane resin injection is water-resistant, so it won’t wash away like the soil it replaced. If the slab has also dropped, we can lift it back towards level in the same visit (see Concrete Jacking).