Addressing Playground Trip Hazards with Targeted Slab Re-levelling

Sections of the school’s concrete playground area had subsided near a set of stairs, creating uneven slab levels and presenting a safety and trip hazard in a high-use area. A key site constraint was the presence of strip drains adjacent to the affected slabs. Any lifting work needed to be carefully controlled to avoid crushing or damaging the drains as the concrete was returned to position.

The school environment also required a fast, contained approach that could be completed with minimal disruption, avoiding major demolition, excavation or extended downtime. Because water movement through open joints can contribute to soil washout beneath concrete slabs, the repair also needed to help reduce the risk of future movement by sealing the joints after the slabs were re-levelled.

Mainmark injected Teretek® directly beneath the affected concrete slabs in a controlled, staged process. As the resin expanded, it filled voids, providing ground improvement beneath the concrete, progressively re-supported and lifted the slabs. Once the slabs had been re-levelled, the joints were cleaned out, primed and sealed.

This final step helped improve the finished appearance of the concrete surface while also reducing the risk of future water ingress through the joints. By limiting water movement beneath the slabs, the joint sealing works helped protect the supporting soils from further washout and assisted in extending the service life of the repaired concrete area.

Mainmark provided a complete repair approach, combining slab re-levelling with joint sealing to address both the immediate surface issue and one of the factors that could contribute to future movement. By filling voids directly beneath the slabs, Mainmark helped restore support to the affected concrete without the need for disruptive demolition, excavation or slab replacement.

Following the lift, the joints were cleaned, primed and sealed, improving the overall finish of the area while helping protect against future water ingress and soil washout beneath the slabs. The project was completed in one day, allowing the school to address the safety issue quickly and efficiently with minimal disruption to daily operations.