Mudjacking in Sandy Springs, GA

When a section of concrete drops, the slab itself is often still sound. The problem is the soil underneath. Mudjacking fills the empty space below the slab and raises it back into place, usually for much less disruption than tearing it out and pouring new.

What mudjacking is and when it makes sense

Mudjacking is a way of raising a settled concrete slab without removing it. We drill a few small holes through the slab, then pump a slurry of soil, cement and water into the space underneath. As the slurry fills the void, it pushes up on the concrete and lifts it. Once the slab is back where it should be, we patch the holes and the slurry firms up into a solid base.

It works best on slabs that have dropped as one piece or in a few large pieces. A driveway panel that sank an inch at the garage, a front walk that tips toward the house, or a patio that now holds water near the back door are all good candidates. It does not suit concrete that is badly broken into small chunks, crumbling at the surface, or so thin that it will not survive being lifted.

Signs a slab has settled

Settling tends to happen slowly, so it is easy to stop noticing it. A few things are worth checking every so often:

• A trip edge where two sections of a walkway or driveway meet
• Water pooling on a patio or running toward the foundation instead of away from it
• A gap opening up between a slab and the house, garage or steps
• Steps that rock or lean, or have pulled away from the porch
• A garage slab or driveway apron that has dropped below the garage floor
• Cracks that are wider at one end, which often means one side has sunk more than the other

What usually causes concrete to sink in Sandy Springs

Most of the soil around Sandy Springs is the red Georgia clay common across the Piedmont. Clay holds water and swells when it is wet, then shrinks and cracks when it dries out. Over a few hot summers and wet winters, that cycle can leave gaps under a slab where the soil has pulled away.

Heavy rain plays a part too. Our storms can drop a lot of water in a short time, and on sloped lots that water often finds its way under the edge of a driveway or patio and carries fine soil with it. Downspouts that empty right beside a slab are one of the most common causes we see. Over time the water washes out a pocket underneath and the concrete settles into it.

Many homes here sit on wooded lots, and large oaks and pines take a lot of water out of the ground. Roots can also lift one side of a slab while the other side sinks. When a tree has been removed, the roots left behind slowly rot and leave soft spots.

Finally, the base under the concrete matters. On some older properties the fill under a driveway or patio was never compacted well when it was poured. It settles for years afterward, and the slab follows it down.

Mudjacking or replacement

We will tell you honestly which one we think your slab needs. Mudjacking is usually the better choice when the concrete is in fair shape and the main problem is that it has dropped. You keep the slab you have, there is far less mess, and the area can generally be used again soon after the work is done.

Replacement is the better choice when the concrete itself has failed. If a slab is broken into many small pieces, is flaking badly at the surface, or has been patched so many times that there is little original concrete left, lifting it only puts a worn-out slab back at the right height. In those cases new concrete is money better spent.

There is also a middle case. If a slab has sunk because water keeps washing soil out from under it, lifting it without dealing with the water means it is likely to settle again. Sometimes the right answer is mudjacking plus a change to a downspout, a gutter or the grading beside the slab. We will point that out when we see it.

What a visit involves

The first step is a look at the concrete in person. We check how far each section has dropped, where the low points are, whether the slab is cracked or still in one piece, and where water is coming from. We also look at what is nearby, such as the foundation, steps, retaining walls or drains, because those often explain why the slab moved.

If mudjacking is a good fit, the work itself is fairly straightforward. We drill holes in a planned pattern, usually an inch or two across. We pump slurry in slowly and watch the slab as it rises, because lifting too fast or too far can crack it. Once each section is level, or sloped the way it should be to shed water, we fill the holes with cement and clean up.

For a typical walkway or patio, the job is usually done in a single visit. You will see the patched holes afterward. They are small and neat, but the patch will not be a perfect color match to older concrete.

Before we arrive

Keeping the slab level afterward

Mudjacking deals with the empty space under a slab, but the soil around it is still Sandy Springs clay. A few small habits help the lift last:

• Make sure downspouts empty well away from driveways, walkways and patios
• Keep gutters clear so they do not overflow onto the ground beside the concrete
• Fill and seal the joints and edges where water can get under the slab
• Watch for new low spots after heavy storms and call early if you see them