Different Problems, Not Just Different Prices
These options address different situations, and framing the decision purely on cost misses that.
Leveling addresses a support problem. The concrete is sound and the ground beneath it moved or washed away. Foam fills the void and restores the elevation.
Replacement addresses a concrete problem. The material itself has deteriorated to the point that restoring its position does not restore its function.
The cost difference follows from that rather than being the thing to optimise. Our concrete leveling page covers the lifting service.
What Each One Involves
Leveling. Ports drilled, foam injected, void filled, slab raised, ports patched. A few hours for a typical residential job, minimal disruption, no spoil, and the surface usually back in service the same day.
Replacement. Existing slab broken out and removed, spoil disposed of, subgrade prepared and compacted, forms and any reinforcement set, concrete poured and finished, and cure time before the surface takes load. Days rather than hours, and the area is out of use throughout.
Side by Side
| Leveling | Replacement | |
|---|---|---|
| Addresses | Loss of support | Deterioration of the concrete |
| Typical duration | Hours | Days, plus cure time |
| Surface out of service | Usually same-day return | Several days minimum |
| Spoil and disposal | None | Substantial |
| Relative cost | Lower where concrete is sound | Higher |
| Appearance result | Existing surface, small patches | New surface, uniform |
| Addresses the original cause | Only if paired with drainage work | Only if subgrade is corrected |
| Opportunity to change layout | No | Yes |
| Durability | Good where concrete is sound | Good, given proper subgrade prep |
When Leveling Wins
- The concrete is structurally sound and lifts as a unit.
- You need the surface back in service quickly.
- Disruption matters, for a business entrance or a shared access.
- The appearance of the existing concrete is acceptable.
- The settled area is a defined section rather than everything.
- Budget favours addressing the functional problem now.
When Replacement Wins
- The concrete has genuinely failed: heavy spalling, extensive cracking, exposed corroded reinforcement.
- The slab is broken into many fragments and will not lift as a unit.
- The slab is too thin for the load it now carries.
- You want to change the layout, the finish, or the drainage.
- The concrete is being replaced anyway as part of a wider project.
- Repeated leveling has not held because the subgrade problem is severe.
Our guide on which concrete surfaces can be leveled covers the condition assessment that determines which group a slab falls into.
The Cause Sits Underneath Both
Neither option addresses why the slab settled, unless you deliberately include it.
If subgrade erosion from a downspout, an irrigation leak, or a grading problem caused the void, that source is still there after either a lift or a repour. New concrete on a washing-out subgrade settles too, just later.
Where we can see a source, we will identify it. Addressing it might mean redirecting a downspout, which is trivial, or it might mean drainage work, which is a separate scope. Either way it is worth knowing before choosing between the two options.
The partial option
On larger areas with variable condition, mixing approaches is often the best value. Remove and repour the one deteriorated panel, lift the sound ones either side. The scope should state where the boundary sits and how the new pour ties into the retained concrete, because that junction is where a poorly specified job shows first.