Your questions, answered

Visible dips, trip edges between adjoining slabs, doors that drag, water pooling on a surface that once drained cleanly, and cracks running across the slab are all signs worth investigating. Left alone, the voids beneath the slab tend to grow: water ingress washes out more fines, the load-bearing area shrinks, and the surface settles further. The longer the movement continues, the greater the scope of work required to correct it.

Polyurethane resin is injected through small holes drilled into the slab. The resin expands beneath the concrete, filling voids and raising the slab back toward its original position. The drilled holes are then filled. The process works on driveways, warehouse floors, car parks, loading bays, road slabs and a range of other surfaces. A specialist will assess the slab condition first and advise whether re-levelling is appropriate for the specific situation.

Price depends on the size of the area, the extent of the subsidence, how accessible the slab is, and the type of surface. A driveway panel costs considerably less than a warehouse floor with widespread void formation beneath it. Submit an enquiry describing what you have found and the specialist firm will price the job after reviewing the site. No figure can be given before the slab has been looked at.

A local specialist firm handles the site visit, assessment and all physical work. Their operatives drill, inject the resin, monitor the lift and make good the surface. Concrete Levelling takes the enquiry; from that point, the specialist firm appointed to your area manages everything on the ground. Describe your situation in the enquiry and a specialist will be in touch to arrange a visit.

Yes. Polyurethane resin injection is suitable for external slabs provided the concrete itself is structurally sound enough to be lifted rather than replaced. Patios, garden steps, driveways, petrol station forecourts and HGV yards have all been treated this way. If the surface has deteriorated beyond a certain point, the specialist will advise on whether re-levelling or full replacement is the right course. Describe the surface and its condition when you submit your enquiry.

Timing depends on the specialist firm covering your area and their current workload. Larger commercial jobs such as warehouse floors or airport apron sections may require a pre-visit assessment before work is scheduled, which adds time. Residential jobs such as driveways or patios are typically simpler to book. Submit the enquiry with as much detail as possible and the specialist will confirm availability directly with you.

Polyurethane resin injection requires calibrated equipment and training to control the lift accurately. Overfilling a void can crack an already stressed slab. A specialist working only in concrete levelling carries the correct equipment, understands the pressure tolerances for different slab thicknesses, and knows when the method is unsuitable. A general contractor repairing a sunken slab by other means may disturb adjacent slabs or leave underlying voids unaddressed.