Mudjacking and foam concrete leveling
Raise a settled slab and fill the hollow under it, usually in an afternoon, without tearing anything out.
A slab sinks when the ground under it gives way. In the Red River Valley that usually means wet lake clay compressing, backfill settling, or meltwater carrying soil out from under the edge. Leveling fills the empty space from above and uses that fill to push the concrete back up.
What can be lifted?
- Driveway slabs and garage aprons
- Front walks and public sidewalk panels
- Patios and back stoops
- Front steps that have tipped or dropped
- Some garage and basement floors, depending on what's under them
What happens on the day?
- Look and measure. The contractor checks how far each slab dropped, looks for cracks that go all the way through, and asks where your downspouts and sump line drain.
- Drill. Holes go in a pattern planned for that slab.
- Fill and lift. Slurry or foam goes in, filling the void first, then raising the slab slowly so it doesn't crack.
- Patch and seal. Holes are filled, and the joints are sealed so water can't wash out the base again.
How do the two methods compare?
| Mudjacking | Foam leveling | |
|---|---|---|
| What's pumped | Cement-based slurry | Two-part polyurethane |
| Hole size | About 1 to 2 inches | About 3/8 to 5/8 inch |
| Weight on the soil | Heavy | Very light |
| Back in use | Usually the next day | Often within an hour |
| Usual cost | Lower | Higher |
Does soft clay change the choice?
It can. Grand Forks sits on old Lake Agassiz clays that the state geological survey describes as soft and expansive. Some contractors prefer foam on that kind of ground because it adds so little weight. Others use slurry and get lasting results by fixing the drainage at the same time. Ask the contractor to explain the reasoning for your slab.
When isn't leveling the answer?
If a slab is broken into many pieces, badly scaled on top, or has dropped several inches because water keeps running under it, replacement or a drainage fix may be better value.
What affects the price?
- Number and size of slabs
- How far they need to come up and how big the void is
- Slurry or foam
- Access for the trailer and hoses
- Joint sealing and crack repair after the lift
We don't quote prices. The contractor sets the price after measuring the slab, finding the void and working out why it dropped, so treat any figure you hear before a site visit as a rough guess.
Where we connect you with help
Common questions
How long does a lifted slab stay level?
Mostly that depends on whether the cause is fixed. With downspouts and drainage keeping water away, a lift can last many years. If meltwater keeps running under the slab, it can drop again.
Can concrete be lifted in a Grand Forks winter?
Frozen ground limits what can be done. Foam can be installed in colder weather than slurry, but most contractors here do leveling from spring thaw to freeze-up.
Related services
- Sidewalk repair and city repair lists
- Driveway and garage apron repair
- Steps, stoops and patios
- Joint sealing and crack repair
More background: Grand Forks concrete repair guide.
Slab dropped after the thaw, or a sidewalk on the city's repair list?
Call and a local mudjacking contractor will come look at it and quote the repair.