After Concrete Levelling: What to Expect

Most questions about concrete levelling relate to what happens after the crew leaves. The works themselves take a few hours. What follows is straightforward but worth knowing in advance. Our how it works page covers the works themselves; this one starts when they finish.

The first few hours

The injection holes (typically 12–16mm in diameter) will have been filled flush with a mortar or resin compound. On a clean surface, you'll see a grid of small filled circles following the drilling pattern. On a textured or weathered driveway, they blend in within a few weeks.

Foot traffic is safe immediately. For vehicles, most contractors recommend waiting one to two hours before driving on the treated area. The resin reaches working strength faster than this, but the cautious interval costs nothing.

Over the following 24 hours, the injected material continues to cure, gaining compressive density. There's no need to stay off the surface during this period, but avoiding concentrated point loads directly over the injection zone (heavy plant, scaffolding) is sensible on the first day.

What the finish looks like

Resin injection lifts and stabilises concrete. The surface itself is unchanged. Any surface cracks, weathering, or staining that existed before the works will still be there afterwards. What changes is the level.

If the surface condition was already poor before the slab settled, levelling and resurfacing are two separate jobs. Once the slab is stable and level, a surface seal or thin overlay can be applied. That's a separate quote and ideally a separate contractor visit after the resin has fully cured, typically 48–72 hours after injection.

The injection holes are the only visible evidence of the work on most surfaces. If matching the existing surface colour is important (decorative concrete, coloured impregnated driveways), ask the contractor in advance whether they offer colour-matched hole fill. Most carry a limited range; alternatives include filling after the fact with a matching mortar mixed to the existing colour.

How to confirm it's worked

A long spirit level or straight edge across the previously sunken section is the straightforward check. Most contractors will confirm the lift achieved on the day, and many provide before-and-after measurements as part of their documentation.

For residential jobs, the real-world checks are often more convincing than a spirit level:

• Standing water should no longer pool in the settled area after rain
• Doors or gates that were catching should clear again
• The trip edge at the joint, if there was one, should have reduced or disappeared
• A garden hose run across the surface should flow away from the house

These are the things homeowners notice and that confirm the outcome in practical terms. For commercial sites, a follow-up TR34 measurement is the equivalent confirmation for floor flatness.

Longevity and what the guarantee covers

Polyurethane resin in stable ground conditions carries a design life of 25 years or more. In UK clay areas with active seasonal movement, some re-treatment may be needed within that period. For most properties this doesn't happen. See why UK clay soils cause concrete to sink for the regional risk picture.

Reputable UK contractors offer guarantees ranging from 5 to 20 years. Before signing, clarify what the guarantee covers. There is a meaningful difference between a guarantee on the resin material (covering material defect or decomposition) and a guarantee on the level achieved (covering re-settlement). Ask specifically which applies, and whether re-settlement due to continued clay movement is included or excluded. The answer will tell you both about the contractor's confidence in their work and the nature of the ground conditions they found on site.

Any guarantee should be issued on headed paper with a company registration number. A sole trader offering a verbal 10-year guarantee is not the same thing. To start the process for your property, request a free survey.