Larkspur Mudjacking

The reason most people finally call about a sunken slab isn't how it looks. It's the wheelbarrow. Or the trash cart that wants to tip every Tuesday, or the plow blade that catches the same lip every storm, or the load of firewood you're walking from the truck to the porch across a lip that grabs your boot in the dark. Sunken concrete is a daily nuisance long before it's a hazard.

Mudjacking hands that surface back to you fast. We core a hole pattern through the panel, force a dense sand-and-cement grout into the cavity below it, and ride that pressure upward until the slab reads level. Nothing gets demolished. Nothing needs a month of curing before you use it. You're back on the concrete you already own, most often the same day.

What slurry is and why its weight is the whole conversation

The material we pump is a screened sand, portland cement, and water grout, blended thick enough to hold a load and loose enough to run sideways into every pocket of the void. It cures into a hard pad and stays there permanently. That permanence is the selling point. It's also the constraint.

Grout is heavy. Filling a washed-out cavity with something dense is exactly right when the soil below is competent and all you lost was the fines that rain carried off. It's exactly wrong when the panel dropped because the dirt underneath is soft and overloaded already, since you'd be piling more weight on the thing that gave out. So the first hour of any lift out here is diagnosis, not pumping. We probe, we look at where roof and hillside water goes, and if slurry is the wrong tool we say so and talk about foam or a rebuild instead. Larkspur lots make that call more often than metro lots do, because a lot of these pads sit on cut-and-fill benches carved into a slope.

What goes back on a lifted slab, and when

How lift day runs on a wooded Larkspur lot

• We walk the route first and figure out where the rig parks and how far the hose has to reach
• Grades get shot with a laser so the target is a number, not somebody's eyeball
• Hole pattern gets laid out to spread pressure across the panel instead of concentrating it
• Cores drilled, spoil vacuumed up, nothing tracked over your flagstone or into the pines
• Grout pumped in stages while a second set of eyes watches the joint line rise
• Pumping stops the instant the panel reads level, because pushing past level cracks concrete
• Holes packed, troweled flat, and tinted toward the color of your slab
• Joints cleaned and resealed so the next storm doesn't wash straight back under the fill

Frost, thaw, and picking your month

We pump from the time the ground releases in spring until it locks up in late fall, and at 6,720 feet that window opens later and shuts earlier than it does closer to town. June through October is the reliable stretch. If you get to choose, choose autumn. A panel back at grade before the snow flies sheds meltwater instead of cupping it into a puddle that refreezes overnight and pries the joint another notch wider.

Frozen ground ends the season, and not because we're soft about the cold. A slab locked into frost won't rise evenly no matter how much pressure sits behind it, and grout wants unfrozen dirt around it while it sets. December calls become March appointments almost every time.

Rain counts for less here than it does on a pour, since everything cures out of the weather beneath your concrete. We still stand down during a real soaker. Soaked ground under a dropped panel behaves unpredictably, and a lift made into firm soil is the only kind that stays put.