Mudjacking cost

Mudjacking a settled concrete slab costs $500 to $2,000 per area, typically around $1,200. Polyurethane foam lifting costs $800 to $2,500 for the same job. Replacing the slab costs $8 to $20 a square foot, which is usually three to five times either.

It works when the concrete is intact and the ground under it has washed out or compacted. It does not work when the slab is broken.

What it costs

How it works

Holes about an inch or two across are drilled through the slab. A slurry or an expanding foam is pumped underneath. The material fills the void, then lifts the slab back to level. The holes are patched.

It takes a few hours and the slab is usable the same day with foam, or within 24 to 48 hours with mudjacking.

Mudjacking uses a cement and soil slurry. Cheaper, heavier, larger holes, and the material can itself compress over decades. Well proven and it has been done for seventy years.

Polyurethane foam uses a two-part expanding foam. Lighter, so it adds almost no load to the soil that failed in the first place, smaller holes, waterproof, and cures in minutes. Costs more and is the better product on poor soil.

Foam is generally the better choice on anything where the soil is questionable, which is most of the situations that caused the settlement.

When it works and when it does not

It works when the slab is structurally sound, the settlement is from a void or compaction under it, and there is somewhere to lift it back to.

It does not work when:

• The slab is cracked into several pieces that will not move together
• The concrete is spalling and crumbling
• The cause is still active, such as a leaking pipe washing soil out
• The slab is a structural element carrying a load it was never designed for
• The soil beneath is expansive clay that will move again next season

That third point matters most. Lifting a slab over a leaking water line is a repair with a schedule attached. Find out why the soil went before paying to fill the space it left.

Slab lifting or replacement

Lift when the slab is sound and you want the trip hazard and the drainage fixed. Replace when the concrete itself has failed, or when you were going to replace it in a few years anyway.

Frequently asked questions

How long does it last?

Foam lifting is generally permanent as long as the underlying cause is resolved. Mudjacking can settle again over ten to twenty years because the slurry is heavy and compresses. Both fail early if the water that caused it is still running.

Will the cracks disappear?

No. Lifting raises the slab; it does not repair the concrete. Existing cracks can be filled afterwards and will still be visible.

Can it lift a house foundation?

Foam is used for some slab-on-grade foundation work, and that is engineering rather than a driveway repair. Settling house foundations are usually piered rather than lifted. Get an engineer.

Is it worth it on a badly cracked driveway?

No. If the slab is in pieces, lifting moves the pieces separately and the result is worse. That is a replacement.

What causes the void in the first place?

Water. Poor drainage washing soil out, a downspout discharging at the edge, a leaking pipe, or fill that was never properly compacted when the slab was poured. Fix that first or you are buying the repair twice.