Mudjacking vs. Replacing a Sunken Driveway, Sidewalk or Stairs

Walk around enough neighborhoods in Kenner or Metairie and you'll spot it: a sidewalk slab that dropped an inch below its neighbor, a driveway that tilts toward the garage, front steps pulling away from the porch. These are more than eyesores. A raised edge is a place to trip, and a tilted slab sends water toward your house. The good news is that sunken concrete can often be lifted. The question is whether it should be.

Why concrete sinks in the first place

Concrete is heavy and rigid, and it only works if the ground under it stays put. In our area the ground doesn't. Soil washes out from beneath a slab after heavy rain. Fill settles. Downspouts dump water in the same spot for years. A leaking pipe can carve out a pocket under a driveway without anyone noticing.

The slab then has nothing under it, so it drops. That's the same process behind soft floors and settling houses, only outside. The concrete didn't fail. What was holding it up did. Stairs and sidewalks are the usual first places you notice it, because they're small, they sit right at the edge of the house and they're the parts people walk on every day. A driveway can sink for a long time before anyone pays attention, but a step that has dropped away from the porch gets noticed the first time somebody stumbles.

What mudjacking is

Mudjacking raises fallen concrete on sidewalks, driveways and stairs without breaking it out. We inject a mixture of topsoil and types of cement underground through small holes in the slab. The mixture fills the empty space and pushes the concrete back up to where it belongs. When the work is done, the holes get patched and you still have the same slab you started with.

The big advantages are simple. You keep your existing concrete, there's far less mess than a tear-out, and you avoid hauling away a broken driveway and pouring a new one.

When lifting makes sense

Mudjacking works best when the concrete itself is still sound and the only problem is that it sank. Look for these situations:

• A slab that dropped as one solid piece with only minor surface cracks
• A sidewalk section that's uneven with its neighbors and creating a trip edge
• Steps or a stoop that tilted away from the house
• A driveway or patio slab that now slopes the wrong way
• Concrete otherwise in good condition that you'd rather not pay to rebuild

If that sounds like your slab, lifting is usually the first thing to consider.

When replacing is the better call

Some concrete is past saving. If a slab has broken into many pieces, crumbled at the edges or cracked all the way through in several places, lifting it just raises a pile of broken parts. Pushing up a slab that's already falling apart won't hold. You'd be paying to lift concrete that will crack again the first time a car pulls onto it, and you'd still have a rough surface to deal with. In those cases the right move is to take out the cracked concrete and start fresh.

That's something we handle too. We remove unwanted cracked concrete, so you don't have to hire one company to lift and another to demolish. We'll look at the slab, tell you what we see and whether lifting or removal makes more sense, and not push you toward whichever job is bigger.

Fix the cause or it will sink again

Here's the part that gets skipped. If the soil washed out because of a downspout, a low spot or a leaking line, lifting the concrete without dealing with the cause only buys time. The water will keep working on the ground until the slab drops again. Part of a good visit is figuring out why it sank.

Because we're plumbers first, we can tell you if a line is part of the story. Between leak detection equipment and video line inspections, we can check whether water from a pipe is what hollowed out the ground. If it is, that gets fixed too.

Get it looked at

A sunken walkway is an easy thing to put off, right up until someone trips on it. We give free same-day estimates across New Orleans, Metairie, Kenner, Houma and Thibodaux, and Mark Peterson, our Louisiana Master Plumber, is on every job. We've been family and locally owned since 1979. You can see what the work involves on our mudjacking page. To have a look at your driveway, steps or sidewalk, call us at (504) 461-5193.